Effects of dietary metabolizable energy and lysine on carcass characteristics and meat quality in Arbor Acres broilers *.
ABSTRACT : An experiment was performed to evaluate the effects of dietary metabolizable energy (ME) and lysine lysine (lī`sēn), organic compound, one of the 20 amino acids commonly found in animal proteins. Only the l-stereoisomer appears in mammalian protein. on carcass characteristics and meat quality in Arbor Acres (AA) broilers from 1 to 56 days of age. A total of 2,970 1-d-old male broiler broiler
a young (about 8 weeks old) male or female chicken weighing 3 to 3.5 lb. chicks were randomly allocated to nine dietary treatments (three ME levels in combination with three lysine levels), and dietary ME and lysine concentrations were formulated by varying corn, soybean soybean, soya bean, or soy pea, leguminous plant (Glycine max, G. soja, or Soja max) of the family Leguminosae (pulse family), native to tropical and warm temperate regions of Asia, where it has been meal, tallow tallow, solid fat extracted from the tissues and fatty deposits of animals, especially from suet (the fat of cattle and sheep). Pure tallow is white, odorless and tasteless; it consists chiefly of triglycerides of stearic, palmitic, and oleic acids. , and L-lysine sulfate sulfate, chemical compound containing the sulfate (SO4) radical. Sulfates are salts or esters of sulfuric acid, H2SO4, formed by replacing one or both of the hydrogens with a metal (e.g., sodium) or a radical (e.g., ammonium or ethyl). concentrations. Live body weight (BW), carcass weight (CW), dressing percent, breast muscle weight (BMW BMW
in full Bayerische Motoren Werke AG
German automaker. Founded as an aircraft engine manufacturer in 1916, the company assumed the name Bayerische Motoren Werke and became known for its high-speed motorcycles in the 1920s. ), yield of breast muscle, muscle color (CIE (Commission Internationale de l'Eclairage, International Commission on Illumination, Vienna, Austria, www.cie.co.at) An international organization that sets standards for all aspects of lighting and illumination, including colorimetry, photometry and the measurement of visible and L*, a*, and b*), pH values 45 min and 24 h postmortem postmortem /post·mor·tem/ (post-mort´im) performed or occurring after death.
Relating to or occurring during the period after death.
See autopsy. (pH45, and pH24), meat shear force value (SFV SFV San Fernando Valley (California)
SFV Schweizerischer Fussballverband (Swiss Soccer Association)
SFV Simple File Verification
SFV Semliki Forest Virus
SFV Straight-Fixed-Variable ), and water loss rate (WLR WLR Water and Land Resources (King County, WA)
WLR Wholesale Line Rental
WLR Weekly Law Reports (UK)
WLR Wafer Level Reliability
WLR Weapons Locating Radar
WLR Buoy Tender, River ) were evaluated. Results showed that live body weight and dressing percent increased (p<0.05) as dietary energy increased. Higher dietary lysine content improved breast muscle weight. Neither carcass weight nor yield of breast muscle was affected by dietary energy or lysine content. Higher ME increased the b* value (p = 0.067) and pH24 value (p<0.05), whereas it decreased SFV (p<0.05) and WLR (p = 0.06). Only water loss rate was influenced (p<0.01) by dietary lysine, which was higher in broilers from the high lysine diet as compared to those from medium or low lysine diets. The pH45 value and L* value of breast muscle were not affected by ME or lysine. Significant interaction of dietary ME and lysine was found on a* value of breast muscle. These results indicated that dietary ME and lysine had important effects on breast muscle growth and meat quality, however their effects were different. Different concentrations of dietary ME and lysine might be considered to improve meat quality. (Key Words : Metabolizable Energy, Lysine, Carcass Trait, Meat Quality, Broiler)
Poultry selection, aiming to reduce breeding costs by improving production of poultry, has progressed continually since the early 1970s and resulted in a very large increase in growth rate of chickens. At the same time, the growth, structure or overall metabolism of muscle are also modified by such selection, probably resulting in modifications affecting technological and sensory characteristics of meat (Santoso, 2002; Remignon and Bihan-Duval, 2003).
Nowadays, poultry quality, which is defined by a combination of multiple factors, has become a primary focus for producers, packers, processors, retailers and consumers. Muscle color and texture are always the two most important factors that influence meat quality. Fletcher et al. (2000) stated that cooked product appearance was significantly associated with raw meat color. Moreover, it is suggested that lightness values could be used as an indicator of poultry breast muscle quality for evaluating the incidence of the PSE-like (pale, soft, and exudative exudative
of or pertaining to a process of exudation.
a disease of young pigs and chickens caused by a nutritional deficiency of vitamin E. Characterized by severe edema of the subcutaneous tissues. ) condition (Barbut, 1993; Owens et al., 2000). Meat pH, tenderness and water holding capacity are attributes of muscle texture that have been studied most extensively. Meat pH is determined by muscle glycogen glycogen (glī`kəjən), starchlike polysaccharide (see carbohydrate) that is found in the liver and muscles of humans and the higher animals and in the cells of the lower animals. content and its degradation rate. A rapid pH drop results in earlier onset of rigor rigor /rig·or/ (rig´er) [L.] chill; rigidity.
rigor mor´tis the stiffening of a dead body accompanying depletion of adenosine triphosphate in the muscle fibers. and greater degree of rigor shortening, which determines the tenderness of meat (Khan, 1974). Muscle contraction is also controlled by the glycogen reserves ante-mortem and their breakdown rate postmortem. Meanwhile, rapid glycogen breakdown results in increased acidification acidification
a technology used by processors to preserve foods by adding acids (such as acetic, citric, phosphoric, propionic and lactic acid) and thereby reduce the risk of growth of harmful bacteria. , and at this pH value, usually the isoelectric point isoelectric point
The pH at which the electrolyte concentration of an amphoteric substance such as protein is electrically zero because the concentration of its cation form equals the concentration of its anion form. of muscle, most proteins in the myofibril myofibril /myo·fi·bril/ (-fi´bril) muscle fibril; one of the slender threads of a muscle fiber, composed of numerous myofilaments. myofi´brillar
n. become denatured and can precipitate. The relaxed proteins decrease their capacity to hold water which is characterized by high water loss rate (WLR). Muscle glycogen pools might be manipulated through diets and the rate of glycolysis glycolysis (glīkŏl`ĭsĭs), term given to the metabolic pathway utilized by most microorganisms (yeast and bacteria) and by all "higher" animals (including humans) for the degradation of glucose. was reduced in pigs fed a muscle glycogen reducing diet (Rosenvold et al., 2003).
Dietary composition and nutrient content are potent regulators of muscle development and metabolism (Grizard et al., 1995, 1999). Studies of dietary factors on meat quality were focused on vitamins and trace minerals. Decreased shear force values were obtained by injecting Ca[Cl.sub.2] into the muscle of lambs (Carpenter et al., 1997; Clare et al., 1997). D'souza et al. (1998) reported that supplementing Mg to diets 5 days before slaughter increased pH value and decreased water drip loss. Addition of Mg to diets increased the redness of the longissimus thoracis muscle of growing-finishing pigs growing-finishing pigs
pigs in the 50 to 250 lb (25 to 100 kg) body weight class being grown and fattened for slaughter. (Apple et al., 2000). Other studies reported that Cr and Fe had different effects on tenderness, water drip loss, and color of poultry meat (Edens, 1997; Ruiz et al., 2000). Dietary composition and/or feed additives have been shown to affect muscle color of pigs (Rosenvold et al., 2001; Stoller et al., 2003), sheep and cattle (Brandt et al., 1992; Boleman et al., 1996; Geay et al., 2001), and meat tenderness of cows (Boleman et al., 1996) and beef steers (Bruce et al., 1991). Conjugated linoleic acid Conjugated linoleic acid (CLA) refers to a family of many isomers of linoleic acid (at least 13 are reported), which are found primarily in the meat and dairy products of ruminants. As implied by the name, the double bonds of CLAs are conjugated. decreased breast muscle redness of broilers (Du and Ahn, 2002). Deficiency in lysine reduced body growth and had an effect on the development of the pectoralis major muscle The Pectoralis major is a thick, fan-shaped muscle, situated at the upper front (anterior) of the chest wall. It makes up the bulk of the chest muscles in the male and lies under the breast in the female. and the sartorius muscle sar·to·ri·us muscle
A muscle with origin from the anterior superior spine of the ilium, with insertion into the medial border of the tuberosity of the tibia, with nerve supply from the femoral nerve, and whose action flexes the thigh and leg and in growing chickens (Tesseraud et al., 1996a, b).
Despite the relatively important effect of metabolizable energy and lysine on the performance of broilers (Sanz et al., 2000; Ettle et al., 2003; Urynek and Buraczewska, 2003; Hidalgo Hidalgo, state, Mexico
Hidalgo (ēthäl`gō), state (1990 pop. 1,888,366), 8,058 sq mi (20,870 sq km), central Mexico. Pachuca de Soto is the capital. et al., 2004; Noy and Sklan, 2004; Lopez and Leeson, 2005; Aftab et al., 2007), data concerning the effect of nutrition, such as ME, lysine and their interaction effects, on these muscle attributes of poultry were seldom available (Moran and Bilgili, 1990; Tesseraud et al., 2001; Smith et al., 2002). The purpose of the present experiment was to determine the effects of dietary ME, lysine and their interactions on carcass characteristics and meat quality (pH, color, water loss rate, and meat shear force value), and to determine the optimum ME and lysine concentrations for better meat quality in Arbor Acres broilers.
MATERIALS AND METHODS
Animals and diets
In order to evaluate the effects of dietary ME and lysine on carcass characteristics and meat quality in AA broilers, a 3x3 (three levels of ME (low, medium, and high) and three levels of lysine (low, medium, and high)) factorial experiment fac·to·ri·al experiment
An experimental design in which two or more series of treatments are tried in all combinations.
see factorial experiment. was conducted. A total of 2,970 1-d-old AA broilers were randomly allocated to nine dietary treatments with five replicates of 66 birds per replicate pen, each equipped with a raised-wire floor. There was no significant difference for initial body weight (BW, 35.63 + or -] 0.78 g) across treatment groups. Broilers were vaccinated for Newcastle disease Newcastle disease, pneumoencephalitis, acute viral disease of domestic poultry. Newcastle disease is characterized by sneezing, coughing, and nervous behavior. Affected birds may show tremors, circling, falling, twisting of the head and neck, or complete paralysis. and infectious bronchitis disease at the hatchery hatchery
a commercial establishment dedicated to the hatching of bird eggs to provide day old chicks and poults to the poultry industry.
the contents of unfertilized eggs. Used in petfood manufacture. , at 7 and 21 days of age, respectively. All broilers were housed in an environmentally controlled house with temperature maintained at approximately 35[degrees]C during the first week post-hatch, then decreased gradually to 25[degrees]C for the duration of the trial. Birds received a 24 h lighting regime during the first three days post-hatch, and 23 h lighting with 1 h darkness from 4 days of age onwards. Pens were enlarged whenever needed to provide enough room for normal growth of broilers. Feed and water were provided ad libitum ad libitum
ad libitum feeding
food available at all times with the quantity and frequency of consumption being the free choice of the animal. during the whole experiment period.
In the present study, nine corn-soybean meal-based diets comprising three levels of ME in combination with three levels of lysine were formulated (LL, LM, LH, ML, MM, MH, HL, HM, and HH were symbols for diets with different concentrations of ME and lysine). All nutrient contents except for ME and lysine were formulated to meet or exceed the NRC NRC
1. National Research Council
2. Nuclear Regulatory Commission
Noun 1. NRC - an independent federal agency created in 1974 to license and regulate nuclear power plants (1994) recommendations. Dietary ME and lysine concentrations of the different experimental diets are presented in Table 1. From 1 to 21 days of age, broilers were fed diets contained 12.96, 13.38, and 13.79 MJ of ME/kg in combination with 1.0, 1.1, and 1.2% lysine, respectively. Diets for broilers from 22 to 42 days of age contained 12.96, 13.38, and 13.79 MJ of ME/kg each in combination with 0.9, 1.0, and 1.1% lysine, respectively. Diets containing 12.96, 13.38, and 13.79 MJ of ME/kg in combination with 0.75, 0.85, and 0.95% lysine, respectively, were fed to birds from 43 to 56 days of age. Diet LL, ML, and HL were basal diets, and the concentrations of lysine in diet LM and LH, diet MM and MH, and diet HM and HH were adjusted by adding L-lysine sulfate to the three basal diets, respectively. The composition and nutrient content of basal diets formulated for broilers in different growing phases are shown in Table 2.
At the end of the experiment, two birds with body weights close to the mean were selected from each pen. Feed and water were withdrawn 12 h prior to slaughter. The birds were humanely slaughtered and carcasses harvested. Breast muscle from both sides of the carcass were skinned and deboned for carcass traits, muscle color ([L.sup.*], [a.sup.*], [b.sup.*]), pH value, tenderness and water loss rate measurements.
Carcass characteristics : Live body weight, carcass weight, and weight of breast muscle from both sides of the carcass were measured. Carcass weight was defined as the weight with feather-scalded, eviscerated carcass (with head, neck, blood, and hocks removed) (Dilger et al., 2006). The dressing percent (carcass weight relative to live body weight) and yield of breast muscle (breast muscle weight relative to carcass weight) was calculated.
Muscle pH : At 45 min and 24 h after slaughter, the breast muscle pH was tested at a depth of 2.5 cm below the surface using a Model PHB-10B meter (Shanghai Kang-Yi Instrument Co. LTD LTD 1 Laron-type dwarfism 2 Leukotriene D 3 Long-term depression, see there 4. Long-term disability ., Shanghai, China). All pH measurements were conducted on the anterior end of the right breast. The pH meter was standardized by a two-point method against standard buffers of pH 4.0 and pH 7.0.
Muscle color : The CIE [L.sup.*] (lower values indicate darker color), [a.sup.*] (larger positive values indicate more red color), and b * (higher value indicates more yellow color) values (CIE Commission Internationale de 1'Eclairage, 1976) were obtained 5 min after slaughter from breast muscle, using a hand-held color difference meter (SC-80C, Kangguang apparatus Co. LTD., Beijing, China), with an illuminant il·lu·mi·nant
Something that gives off light.
[Latin illmin D65 and 10 [degrees] standard observer. Five particular spots of muscle free of hemorrhagic Hemorrhagic
A condition resulting in massive, difficult-to-control bleeding.
Mentioned in: Hantavirus Infections
pertaining to or characterized by hemorrhage. , ecchymotic ec·chy·mo·sis
The passage of blood from ruptured blood vessels into subcutaneous tissue, marked by a purple discoloration of the skin.
[New Latin, from Greek lesions or any other abnormal discoloration dis·col·or·a·tion
a. The act of discoloring.
b. The condition of being discolored.
2. A discolored spot, smudge, or area; a stain.
Noun 1. were measured on each muscle (Fletcher, 1999).
Shear force value : A 12.7 mm (diameter) core was removed from the anterior end of each fillet with attached sampler. The cores were boiled in a temperature-controlled bath to an internal temperature of 70 [degrees] C. Upon reaching the desired internal temperature, the cores were removed. Each sample was sheared perpendicular to the grain of the muscle fiber using a 25-kg load cell and crosshead cross·head
A beam that connects the piston rod to the connecting rod of a reciprocating engine.
Noun 1. crosshead - a heading of a subsection printed within the body of the text
crossheading speed of 5 mm/s with a Digital Meat Tenderness Meter of Model C-LM3 (Northeast Agricultural University, Harbin, China). Maximum force measured to cut the cores was expressed as kilogram force (kg.f). For each cooked muscle, the core was sheared in 2 locations and the average of the maximum forces was used for data analysis.
Water loss rate : Water-holding capacity, expressed as water loss rate, was measured by applying a load of 2.25 kg on the fillet core. The released water weight was calculated as the difference between the weight of intact fillet and the pressed fillet.
The pen was used as experimental unit. Data were analyzed by the GLM GLM Global Language Monitor
GLM Global Marine (stock symbol)
GLM Graduated Length Method (ski instruction)
GLM Good Looking Mom (used in pediatric practices)
GLM God Loves Me procedure of SAS (1) (SAS Institute Inc., Cary, NC, www.sas.com) A software company that specializes in data warehousing and decision support software based on the SAS System. Founded in 1976, SAS is one of the world's largest privately held software companies. See SAS System. software (SAS Institute, 1998) for a randomized complete block with a factorial factorial
For any whole number, the product of all the counting numbers up to and including itself. It is indicated with an exclamation point: 4! (read “four factorial”) is 1 × 2 × 3 × 4 = 24. treatment design with dietary ME, lysine, and interaction as main effects. The factorial treatment arrangement consisted of three levels of dietary ME and three levels of dietary lysine. If differences in treatment means were detected, the least significant difference (LSD LSD or lysergic acid diethylamide (lī'sûr`jĭk, dī'ĕth`ələmĭd, dī'ĕthəlăm`ĭd), alkaloid synthesized from lysergic acid, which is found in the fungus ergot ( ) was applied to separate means. A significance level of p<0.05 was used during analysis and other significance levels were also specified whenever necessary.
The effects of dietary ME and lysine content on carcass traits are presented in Table 3. Dietary energy affected live body weight and dressing percent. As expected, live body weight of broilers increased with the increase of dietary energy. Body weight of broilers fed medium and high energy content was significantly higher (p<0.05) than those fed the low energy diet. Dietary ME had the same effects on dressing percent. The broilers fed high energy diets had higher (p<0.05) dressing percent than those fed low energy diets. Live body weight and dressing percent were not influenced by dietary lysine. Broilers fed medium and high lysine diets had higher (p<0.05) breast muscle weight than those fed low lysine diets whereas dietary energy had no significant impact on the weight of breast muscle. Carcass weight and breast muscle yield were not affected by dietary energy or lysine. There was no interaction effect on any of the parameters.
Table 4 shows the effects of dietary ME and lysine on muscle color ([L.sup.*], [a.sup.*], [b.sup.*]), pH value, shear force value and water loss rate. Dietary ME had no significant effects on the breast muscle [L.sup.*] and [a.sup.*] values, though the [b.sup.*] value increased (p = 0.067) with increasing ME. Dietary lysine had no influence on the color of breast muscle. A significant interaction was found on the [a.sup.*] value of breast muscle (p<0.05). This result indicated that differences of [a.sup.*] value between different lysine levels in medium energy diets were significantly greater than differences between lysine levels in low and high energy diets.
The pH value of breast muscle 45 min postmortem was not affected by dietary treatments. However, dietary energy and lysine content had significant effects on pH value 24 h postmortem, shear force value and water loss rate (Table 4). The [pH.sub.24] value increased with the increment of ME content (p<0.01), which was higher in birds fed medium and high ME diets than in those fed a low energy diet. Dietary lysine had no influence on [pH.sub.24]. The breast fillets from broilers fed low ME diets had higher (p<0.05) SFV than those fed medium or high ME diets, whereas dietary lysine had no significant (p>0.05) effect on the tenderness of breast fillets. In this experiment, WLR was measured to evaluate water-holding capacity of muscle. Higher WLR meant lower water-holding capacity. The WLR of breast muscle was affected by dietary ME and lysine concentration. The WLR of breast muscle from boilers fed low ME diets were higher (p = 0.06) compared with those fed medium or high ME diets. Water-holding capacity decreased as dietary lysine concentration increased, and was significantly lower (p<0.01) in broilers fed high lysine diets when compared to those fed low or medium lysine diets. No interaction effect was obtained on [pH.sub.45], [pH.sub.24], shear force value and water loss rate.
Although an inadequacy of any nutrient has repercussions repercussions npl → répercussions fpl
repercussions npl → Auswirkungen pl for the yield of meat or perhaps quality, only a few are of importance in poultry production. In general, these nutrients are energy, protein and phosphorus (Moran, 1999). Effects of dietary energy on the performance of broilers have been studied extensively (Yalcin et al., 1998; Hidalgo et al., 2004; Shyam Sunder et al., 2007) and showed that increasing dietary energy resulted in greater body weight, which was consistent with the present results. High energy levels are linked to high performance while reduction in dietary energy is not always associated with negative effects. Moran (1997) reported carcass quality and skinless-boneless meat yield of male broilers were not impaired when dietary fat was replaced with corn. This result accords with the present experiment. Increasing dietary energy improved body weight, while carcass weight did not suffer from low energy diets. Body fat may account for the increase in body weight of broilers fed high energy diets and carcass weight was not affected by energy.
Sonaiya et al. (1990) showed that male broilers receiving high energy diets had higher carcass weight. These different results might be due to the different breeds of poultry and environmental temperatures used in these experiments. The effect of the dietary energy on dressing percent was supported by Leclercq and Escartin (1987), who stated that increasing dietary energy led to faster growth rate and higher dressing percentage. In the present experiment, dietary energy had no effect on breast meat weight, though Nahashon et al. (2005) reported that breast meat weights of birds fed diets containing 3,150 kcal ME/kg were higher than those of birds fed 3,050 kcal ME/kg diets.
It is well known that dietary amino acids have important effects on carcass characteristics of broilers (Dozier Dozier may be:
Glycogen content and its depletion rate post mortem [Latin, After death.] Pertaining to matters occurring after death. A term generally applied to an autopsy or examination of a corpse in order to ascertain the cause of death or to the inquisition for that purpose by the Coroner . determines pH decline of muscle (Lister et al., 1970), and glycogen in muscle could be manipulated by dietary composition (Rosenvold et al., 2003). Generally, muscle pH has been associated with lots of meat quality attributes, such as meat color, tenderness, water-holding capacity and other characteristics of muscle. Color is one of the most important quality attributes of poultry muscle or meat product for consumer acceptance. Mugler and Cunningham (1972) reviewed many factors influencing poultry meat color, such as bird sex, age, strain and processing procedures. However, limited studies were available expatiating nutritional aspects and their effects on meat quality and the PSE PSE
1. pale soft exudative pork.
2. portosystemic encephalopathy. condition. Smith et al. (2002) reported that wheat-based diets increased broiler breast lightness ([L.sup.*]) and yellowness ([b.sup.*]) and decreased redness ([a.sup.*]) compared to milo- and corn- based diets. Extra dietary supplementation of tryptophan tryptophan (trĭp`təfăn), organic compound, one of the 20 amino acids commonly found in animal proteins. Only the l-stereoisomer appears in mammalian protein. reduced incidence of PSE meat (Adeola and Ball, 1992). Boulianne and King (1995, 1998) reported that pale fillet had significantly greater lightness value, less redness and greater yellowness, whereas dark fillets had lower lightness and yellowness. In the present study, higher ME increased the b* value of breast muscles whereas, lysine had contrasting effects on [b.sup.*] value of breast muscle such that higher lysine concentration decreased muscle yellowness. The functioning mechanism of energy and lysine on the color of muscle remains unclear, and whether the effect was due to pigments present in feed ingredients or changes in protein metabolism Protein metabolism
The transformation and fate of food proteins from their ingestion to the elimination of their excretion products. Proteins are of exceptional importance to organisms because they are the chief constituents, aside from water, of all the soft resulting from dietary lysine content needs further study. El Rammouz et al. (2004) reported ultimate pH (24 h postmortem) was significantly correlated with lightness (r = -0.37) and yellowness (r = -0.36). Livingston and Brown (1981) reported higher muscle pH resulted in darker breast meat. Dark fillets had significantly lower lightness, higher redness, lower yellowness, and higher pH values (Boulianne and King, 1995, 1998; Allen et al., 1997). These findings were confirmed by Yang and Chen (1993). The above results were consistent with the present research, in which increased lightness was associated with higher yellowness and decreased redness.
Much research has been conducted to study the factors influencing meat tenderness and water-holding capacity (Fletcher, 2002). Genetic stock and selection (Smith, 1963), age, sex, location (Castaneda et al., 2005), pre--and post-slaughter chilling (Alvarado and Sams, 2000) and postmortem metabolism (Skarovsky and Sams, 1999) were factors affecting quality of muscle. About 88 to 95% of water in the muscle is held intracellularly within the space between actin and myosin myosin (mī`əsĭn), one of the two major protein constituents responsible for contraction of muscle. In muscle cells myosin is arranged in long filaments called thick filaments that lie parallel to the microfilaments of actin. filaments (Ranken, 1976; Offer and Knight, 1988). Water-holding capacity determines the juiciness, flavor and tenderness of meat (Wood, 1993). Lactic acid lactic acid, CH3CHOHCO2H, a colorless liquid organic acid. It is miscible with water or ethanol. Lactic acid is a fermentation product of lactose (milk sugar); it is present in sour milk, koumiss, leban, yogurt, and cottage cheese. accumulation and the decline in pH post mortem result in protein denaturation denaturation, term used to describe the loss of native, higher-order structure of protein molecules in solution. Most globular proteins exhibit complicated three-dimensional folding described as secondary, tertiary, and quarternary structures. and an overall decrease in muscle water-holding capacity. On the other hand, divalent divalent /di·va·lent/ (di-va´lent) bivalent; carrying a valence of two.
di·va cations in the sarcoplasm, during the rigor mortis rigor mortis (rĭ`gər môr`tĭs), rigidity of the body that occurs after death. The onset may vary from about 10 min to several hours or more after death, depending on the condition of the body at death and on factors in the period, bind to the reactive groups on adjacent protein chains, reducing the electrostatic repulsion repulsion /re·pul·sion/ (re-pul´shun)
1. the act of driving apart or away; a force that tends to drive two bodies apart.
2. between negatively charged groups that maintain their separation (Wismer-Perdersen, 1986). This reaction reduces the space available for water to be retained intramuscularly in·tra·mus·cu·lar
Within a muscle: an intramuscular injection.
in . Rosenvold et al. (2003) reported that a higher digestible digestible
having the quality of being able to be digested.
the proportion of the potential energy in a feed which is in fact digested.
see digestible protein. energy diet induced a reduction in total glycogen stores, which resulted in a higher ultimate pH value. This may account for the lower water loss rate and resultant higher tenderness of breast muscle from birds fed a high energy diet in the present experiment. Another attribute of energy to tenderness of muscle is intramuscular fat. The decrease in shear force value with dietary energy might be due to increased muscular fat content and altered glucose metabolism by decreasing the translocation or expression of glucose transporter-4 (Clarke, 2000). Lyon et al. (2004) also reported that breast fillets from wheat-fed birds required more force to shear compared with breasts from corn-fed birds.
It is clear that dietary lysine content affects the performance and carcass characteristics of broilers. Relatively little research has been conducted to study the density of dietary lysine on the meat quality of broilers. Apple et al. (2004) reported that lysine content had no effect on the pH, drip loss, firmness score and a* value of LM in pigs, and increased the L* value and decreased the [b.sup.*] value. Cameron et al. (1999) found that lower lysine density produced redder and more yellow pork meat than higher density of dietary lysine. No influence of lysine on ultimate pH, shear force value and meat color was observed in this study, whereas increasing dietary lysine content significantly decreased water-holding capacity in the breast muscle. However, the relationship between muscle lysine metabolism, protein turnover and muscle water-holding capacity needed further study.
According to the results obtained in the present study, dietary ME and lysine had significant effects on carcass characteristics and meat quality. These parameters responded to dietary ME and lysine in different ways. Therefore, higher body weight and dressing percentage would be obtained by feeding a higher level of dietary ME to broilers, higher lysine density would produce more breast meat and medium dietary energy and lysine level would produce more tender meat.
Received December 22, 2006; Accepted June 11, 2007
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* Financially supported by National Basic Research Program of China (Project No: 2004CB11750-).
M. Y. Tang, Q. G. Ma, X. D. Chen and C. Ji ** National Lab of Animal Nutrition, College of Animal Science and Technology China Agricultural University, Beijing, 100094, China
** Corresponding Author: Cheng Ji. Tel: +86-10-62732774, Fax: +86-10-62732774, E-mail: firstname.lastname@example.org
Table 1. Dietary ME and lysine levels for Arbor Acres broilers in different growing phases Age (d) Diets (1) 1 to 21 22 to 42 ME (MJ/kg) Lysine (%) ME (MJ/kg) Lysine (%) LL 12.96 1.0 12.96 0.9 LM 12.96 1.1 12.96 1.0 LH 12.96 1.2 12.96 1.1 ML 13.38 1.0 13.38 0.9 MM 13.38 1.1 13.38 1.0 MH 13.38 1.2 13.38 1.1 HL 13.79 1.0 13.79 0.9 HM 13.79 1.1 13.79 1.0 HH 13.79 1.2 13.79 1.1 Age (d) Diets (1) 43 to 56 ME (MJ/kg) Lysine (%) LL 12.96 0.75 LM 12.96 0.85 LH 12.96 0.95 ML 13.38 0.75 MM 13.38 0.85 MH 13.38 0.95 HL 13.79 0.75 HM 13.79 0.85 HH 13.79 0.95 (1) LL to HH represented nine diets with different energy and lysine concentrations. LL = Low energy low lysine; LM = Low energy medium lysine; LH = Low energy high lysine; ML = Medium energy low lysine; MM = Medium energy medium lysine; MH = Medium energy high lysine; HL = High energy low lysine; HM = High energy medium lysine; HH = High energy high lysine. Table 2. Composition and nutrient content of basal diets (1) for broilers in different growing phases Age (d) Diets (2) 1 to 21 Ingredients (%) LL ML HL Corn Soybean meal 55.3 53.0 50.8 Peanut meal 20.9 20.9 21.0 Extruded soybean 7.0 7.0 6.6 Corn gluten meal 2.0 2.0 2.0 Fish meal 5.2 5.6 6.0 Animal tallow 3.2 3.2 3.3 Limestone 2.2 4.1 6.1 Dicalcium phosphate 1.3 1.3 1.3 Peptide additive 1.4 1.4 1.4 Salt 0.2 0.2 0.2 DL-methionine 0.3 0.3 0.3 Premix (3) Total 1.0 1.0 1.0 Calculated composition 100 100 100 ME (MJ/kg) Crude protein (%) 12.96 13.38 13.79 Crude fat (%) 23.00 23.00 23.00 Calcium (%) 4.62 4.62 4.62 Total phosphorus (%) 1.08 1.08 1.08 Available phosphorus (%) 0.66 0.66 0.66 Lysine (4) (%) 0.56 0.56 0.56 Age (d) 22 to 42 Diets (2) LL ML HL Ingredients (%) 62.1 59.3 58.2 Corn 21.3 20.3 17.0 Soybean meal 4.1 4.7 6.0 Peanut meal 2.0 3.0 3.0 Extruded soybean 2.5 2.5 2.9 Corn gluten meal 2.0 2.0 3.3 Fish meal 1.8 4.0 5.5 Animal tallow 1.3 1.3 1.3 Limestone 1.4 1.4 1.4 Dicalcium phosphate 0.2 0.2 0.1 Peptide additive 0.3 0.3 0.3 Salt DL-methionine 1.0 1.0 1.0 Premix (3) 100 100 100 Total Calculated composition 12.96 13.38 13.79 ME (MJ/kg) 21.00 21.00 21.00 Crude protein (%) 4.77 4.77 4.77 Crude fat (%) 0.97 0.97 0.97 Calcium (%) 0.62 0.62 0.62 Total phosphorus (%) 0.54 0.54 0.54 Available phosphorus (%) 0.90 0.90 0.90 Lysine (4) (%) Age (d) Diets (2) 43 to 56 Ingredients (%) LL ML HL Corn Soybean meal 67.8 65.6 63.3 Peanut meal 12.1 12.9 12.6 Extruded soybean 10.3 8.5 9.2 Corn gluten meal 3.0 3.0 3.0 Fish meal 1.0 1.9 1.9 Animal tallow 0.9 1.1 1.1 Limestone 1.1 3.1 5.0 Dicalcium phosphate 1.4 1.4 1.4 Peptide additive 1.0 1.1 1.1 Salt 0.1 0.1 0.1 DL-methionine 0.3 0.3 0.3 Premix (3) Total 1.0 1.0 1.0 Calculated composition 100 100 100 ME (MJ/kg) Crude protein (%) 12.96 13.38 13.79 Crude fat (%) 19.00 19.00 19.00 Calcium (%) 4.85 4.85 4.85 Total phosphorus (%) 1.07 1.07 1.07 Available phosphorus (%) 0.54 0.54 0.54 Lysine (4) (%) 0.42 0.42 0.42 0.75 0.75 0.75 (1) The medium and high lysine diets were formulated by replacing limestone with L-lysine [H.sub.2]S[O.sub.4], respectively. (2) LL, ML, and HL represented basal diets with different ME and low lysine concentrations formulated for broilers in 3 growing periods. LL = Low energy low lysine; ML = Medium energy low lysine; HL = High energy low lysine. (3) The vitamin and mineral premix contained per kg of diet: Vitamin A, 14,711 IU; Vitamin D3, 1,409 IU; Vitamin E, 16 IU; [B.sub.1], 1.1 mg; [B.sub.2], 8.1 mg; [B.sub.6], 4 mg; [B.sub.12], 2 mg; folic acid, 1 mg; pantothenic acid, 11.3 mg; niacin, 60 mg; biotin, 10 mg; manganese, 65 mg; zinc, 55 mg; iron 0.3 mg; copper, 6 mg; iodine, 1 mg; selenium 0.3 mg. (4) The lysine contents in diets were analyzed values. Table 3. Effects of dietary ME and lysine on live body weight, carcass weight, breast muscle weight, yield of breast muscle and dressing percent of 56 day-old broilers Breast Live body Carcass muscle weight (g) weight (g) weight (g) ME (3) L 2,684 (a) 1,929 476.89 M 2,757 (b) 1,940 464.44 H 2,771 (b) 1,965 471.56 SEM (5) 21.20 17.44 7.36 Lysine (4) L 2,722 1,921 443.78 (a) M 2,735 1,951 479.78 (b) H 2,756 1,962 489.33 (b) SEM (5) 21.20 17.44 7.36 Probability value ME 0.012 0.338 0.505 Lysine 0.513 0.239 0.001 ME x lysine 0.817 0.929 0.207 Breast muscle Dressing yield percent (1) (%) (2) (%) ME (3) L 24.99 69.42 (a) M 23.98 70.49 (ab) H 23.56 71.73 (b) SEM (5) 0.47 0.5 Lysine (4) L 23.86 70.49 M 24.14 70.72 H 24.54 70.42 SEM (5) 0.47 0.50 Probability value ME 0.101 0.01 Lysine 0.599 0.907 ME x lysine 0.200 0.391 (1) Breast muscle weight relative to carcass weight. (2) Carcass weight relative to live body weight. (3) L, M, and H represented concentrations of dietary ME. L = Low; M = Medium; H = High. (4) L, M, and H represented concentrations of dietary lysine. L = Low; M = Medium; H = High. (5) Pooled Standard Error of the Mean. (a, b) Means with different superscripts differ significantly (p<0.05). Table 4. Effects of dietary ME and lysine on the color ([L.sup.*], [a.sup.*], [b.sup.*]), pH value 45 min and 24 h postmortem, shear force value (SFV) and water loss rate (WLR) of breast muscle of 56 day-old broilers ME (1) Lysine (2) L * a * b * L L 49.84 3.42 (a) 10.02 M 49.17 4.77 (ab) 9.37 H 50.79 4.17 (ab) 9.07 M L 51.73 6.00 (b) 11.67 M 53.85 2.18 (a) 10.71 H 52.85 2.77 (a) 10.39 H L 51.17 3.87 (ab) 11.37 M 55.71 3.33 (a) 11.68 H 51.90 3.92 (ab) 10.45 SEM (3) 0.66 0.25 0.31 ME L 49.93 4.12 9.49 M 52.81 3.65 10.93 H 52.93 3.71 11.17 SEM (3) 1.15 0.44 0.54 Lysine L 50.91 4.43 11.02 M 52.91 3.42 10.59 H 51.84 3.62 9.97 SEM (3) 1.15 0.44 0.54 Probability value ME 0.116 0.701 0.067 Lysine 0.480 0.231 0.376 ME x lysine 0.635 0.018 0.963 ME (1) Lysine (2) p[H.sub.45] p[H.sub.24] L L 6.17 5.63 (ab) M 6.16 5.54 (a) H 6.13 5.64 (ab) M L 6.07 5.76 (ab) M 6.20 5.80 (b) H 6.13 5.88 (b) H L 6.17 5.86 (b) M 6.06 5.84 (b) H 6.10 5.74 (ab) SEM (3) 0.05 0.04 ME L 6.15 5.61 (a) M 6.13 5.81 (b) H 6.11 5.82 (b) SEM (3) 0.02 0.04 Lysine L 6.14 5.75 M 6.14 5.73 H 6.12 5.76 SEM (3) 0.02 0.04 Probability value ME 0.352 0.001 Lysine 0.682 0.889 ME x lysine 0.065 0.397 ME (1) Lysine (2) SFV (kg.f) WLR (%) L L 2.09 (abc) 31.46 (a) M 2.46 (abc) 35.09 (b) H 2.52 (bc) 39.52 (c) M L 1.70 (abc) 32.36 (a) M 2.45 (ab) 35.03 (ab) H 2.61 (c) 37.10 (bc) H L 1.54 (a) 31.07 (a) M 1.63 (ab) 30.63 (a) H 1.97 (abc) 34.97 (ab) SEM (3) 3.2 2.1 ME L 2.36 (b) 35.36 (b) M 2.25 (a) 34.83 (a) H 1.71 (a) 32.23 (a) SEM (3) 0.26 3.54 Lysine L 1.78 31.63 (a) M 2.18 33.58 (a) H 2.36 37.20 (b) SEM (3) 0.26 3.52 Probability value ME 0.043 0.060 Lysine 0.092 0.001 ME x lysine 0.858 0.527 (1) L, M, and H represented concentrations of ME. L = Low; M = Medium; H = High. (2) L, M, and H represented concentrations of lysine. L = Low; M = Medium; H = High. (3) Pooled Standard Error of the Mean. (a, b, c) Means with different superscripts differ significantly (p<0.05).