Histochemical properties and collagen architecture of M. iliotibialis lateralis and M. puboischiofemoralis in male broilers with different growth rates induced by feeding at different planes of nutrition

1. The histochemical properties and the collagen content and architecture of the iliotibialis lateralis (ITL) and puboischiofemoralis (PIF) muscles were assessed in Red Cornish x New Hampshire cockerels reared on a high nutrient plane for 80 d (H80d), or a low nutrient plane for 80 d (L80d) or 95 d (L95d). 2. Final live weights were 3410 g in H80d, 2810 g in L80d and 3467 g in L95d. Both ITL and PIF muscle weights were lowest in L80d and did not differ between H80d and L95d. 3. ITL muscle was composed of fast-twitch myofibres such as IIA (high reduced nicotinamide adenine dinucleotide dehydrogenase, NADH-DH activity), IIB (low NADH-DH activity) and IIC (intermediate NADH-DH activity). The high percentage of type IIB myofibres in H80d (76.6%) and L95d (76.2%) birds were reflected in low percentages of type IIC myofibres (12.2%) in H80d birds and type IIA myofibres (8.2%) in L95d birds. Percentages of IIA, IIB and IIC myofibres in L80d cockerels were 12.4, 69.8 and 17.6%, respectively. 4. The myofibres in PIF muscle were divided into two basic types, I and IIA, and a transitional form (I-tr) from IIA to I. In the caudal region, all myofibres in H80d and L95d cockerels were type I but in L80d cockerels 15% of myofibres were categorised as type I-tr. In the cranial region, the great majority (52 to 63%) of myofibres were type IIA. Type I myofibres occurred at a higher percentage in H80d (30.5%) than L95d (21.8%) and type I-tr in L95d (15.7%) than H80d (7.3%) and L80d (11.5%). 5. The total amount of collagen was higher in ITL than PIF muscle in every bird group. In both muscles the highest collagen content was in L95d cockerels but the content did not differ between H80d and L80d birds. The thickness of thick and thin perimysia increased with muscle size. The circular collagen fibre in the thick perimysium was larger in ITL (6.1 to 7.0 microm) than PIF (3.7 to 3.8 microm) muscle but did not differ among the bird groups. 6. From these results, it was concluded that feeding on a high nutritional plane promotes growth of the thigh muscles, with accompanying enlargement of the perimysial thickness, no increase in collagen content and various changes of histochemical properties.     

Comparative studies on the histochemical properties of M. iliotibialis lateralis from Kumamoto Cochin crossbred roaster and broiler chickens

1. Histochemical properties of M. iliotibialis lateralis were compared between Kumamoto Cochin (a Japanese native breed) crossbred roasters (KC roasters, 112 d of age) and normal broilers (56 d of age).

2. Myofibres were divided into Types II‐R, II‐I and II‐W showing high, moderate and low reduced nicotinamide adenine dinucleotide dehydrogenase (NADH‐DH) activities, respectively.

3. Subsarcolemmal formazan granules indicating very strong NADH‐DH activity in Type II‐R fibres were observed only in KC roasters. In both sexes the percentage of Type II‐R fibres present was greater in KC roasters than in broilers.

4. These results indicated marked differences in histochemical properties and meat quality between KC roasters and broilers.     

Breed differences in the histochemical properties of the M. iliotibialis lateralis myofibre of domestic cocks.

1. Reduced nicotinamide adenine dinucleotide dehydrogenase (NADH-DH) activity in the M. iliotibialis lateralis was compared histochemically among 7 breeds of cocks. This muscle was composed only of Type-IIA and -IIB fibres. 2. Apparent breed differences were observed in muscle development, the NADH-DH activity in every fibre type, fibre type distribution and fibre diameters. 3. From the results of this study, it was concluded that the muscle characteristics of various breeds were based not only on the fibre type composition, but also the different activities of oxidative enzyme in every type.     

Myofibre composition and total collagen content in M. iliotibialis lateralis and M. pectoralis of Silkie and White Leghorn chickens

1. Using adult Silkie and White Leghorn (WL) chickens, fibre composition and total collagen content were compared between M. iliolibialis lateralis (ITL) and M. pectoralis (PT). 2. Fibres were divided into type IIR and IIW showing strong and weak reduced nicotinamide adenine dinucleotide dehydrogenase activities, respectively. 3. Fibre composition differed markedly between ITL and PT muscle. ITL muscle was composed of both types IIR and IIW fibre but PT muscle of only type IIW Breed difference on composition was noted only in ITL muscle of cocks (type IIR; Silkie 53.8% and WL 37.0%). 4. Total collagen content was greater in ITL muscles and in cocks in both muscles. However, a breed difference was observed only in the PT muscle of hens. 5. In conclusion, the total collagen content was affected by muscle location within the body and by sex rather than by fibre composition.     

Developmental states of the collagen content, distribution and architecture in the pectoralis, iliotibialis lateralis and puboischiofemoralis muscles of male Red Cornish x New Hampshire and normal broilers

1. Developmental states of the collagen content, distribution and architecture in the pectoralis (PT), iliotibialis lateralis (ITL) and puboischiofemoralis (PIF) muscles of male Red Cornish x New Hampshire (RN, 80 d, body weight 2.9 kg) and normal (3.1 kg) broilers were evaluated. 2. In PT muscle the total amount of collagen was significantly greater in RN broilers (3.33 mg/g) than in normal ones (1.71 mg/g). This higher collagen content in RN broilers was based mainly on the closer mesh sizes of endomysial honeycomb. The collagen structures in the perimysia also differed between broiler types, when more collagen fibres were observed in RN broilers. 3. ITL muscle contained total collagen of 4.10 to 5.00 mg/g. Types I and III collagens were distributed on the perimysia at higher percentages in RN broilers (31.6%, 37.2%) than normal (15.6%, 30.8%), respectively. The thick bands of tough collagen fibres characteristic of ITL muscle perimysium in cockerels had not yet developed in these broilers. 4. Total collagen was 4.63 to 6.29 mg/g in PIF material with fascia. In PIF muscle the perimysial collagen fibres had not yet attained their full growth but consisted of densely packed fibrils. PIF muscle was characterised by the earlier maturing collagen structure. 5. These results show that a perimysial collagen structure in broilers is still in an undeveloped state. It is supposed that tenderness of broiler meat is attributed mainly to characteristics of the collagen distribution, in which the majority of types I and III collagens is distributed on the closer mesh of endomysial honeycomb.     

Indirect myosin immunocytochemistry for the identification of fibre types in equine skeletal muscle.

The histochemical ATPase method for muscle fibre typing was first described by Brooke and Kaiser in 1970. However, problems have been found with the subdivision of type II fibres using this technique. To determine whether indirect myosin immunocytochemistry using anti-slow (5-4D), anti-fast (1A10) and anti-fast red (5-2B) monoclonal antibodies with cross reactivity for type I, II and IIa fibres, respectively, in a number of species, could identify three fibre types in equine skeletal muscle, data on fibre type composition and fibre size obtained using the two different techniques were compared. Results indicate that different myosin heavy chains can coexist in single equine muscle fibres. Type I and type II fibres were identified by immunocytochemistry, but subdivision of type II fibres was not possible. Although the percentage of type I and type II fibres was not significantly different for the two techniques, a few fibres reacted with both the 1A10 and 5-4D antibodies.     

Breed differences in the histochemical properties of the M. pubo‐ischi‐ofemoralis pars medialis myofibre of domestic cocks

1. Histochemical properties of M. pubo‐ischio‐femoralis pars medialis (PIF muscle) were compared in 7 breeds of cocks. This muscle was largely composed of Type I fibres and their transitional form (Type I tr). Type IIA fibres were observed in the cranial part.

2. The weight and cross‐sectional area of the PIF muscle increased with increasing body weight. However, the relative muscle development to body weight differed among the 7 breeds.

3. A quarter of Type I fibres were of the transitional variety in bantam fowls. Conversely, few, if any, Type I tr fibres were observed in the large breeds where the muscle was poorly developed.

4. As the histochemical properties of Type I fibres made an effective response to the different body weights and the relative PIF muscle development among breeds, it was concluded that PIF muscle performed an important function in supporting the body weight and maintaining posture.     

Different growth rates of male chicken skeletal muscles related to their histochemical properties

1. Early, M. pubo‐ischio‐femoralis pars medialis (PIF muscle) and late, M. iliotibialis lateralis pars postacetabularis (ITL muscle), maturing muscles were studied. These two muscles contained different populations of histo‐chemical fibre types.

2. The profile measurements of the muscles showed diphasic allometric growth relative to the weights. In the early stage of growth (up to 15 weeks after hatching), the muscle length, width and depth all increased, while in the later stage (from 15 to 35 weeks) muscle growth resulted mainly from the marked increase in the depth and to a lesser degree, from an increase in the width.

3. Type I fibres, observed predominantly in PIF muscle matured earlier than the Type II fibres of ITL muscle.

4. From these results, the detailed process of skeletal muscle growth in the chicken was discussed.     

Growth changes of the collagen content and architecture in the pectoralis and iliotibialis lateralis muscles of cockerels

1. Growth changes of the collagen content and architecture in the pectoralis (PT) and iliotibialis lateralis (ITL) muscles were examined using cockerels from 1 to 14 weeks of age. 2. Total collagen content in PT muscle showed little change, but in ITL muscle reached a maximum at 5 weeks and thereafter decreased slightly until 14 weeks. The collagen content was markedly larger in ITL muscle after 5 weeks. Pyridinoline content of collagen increased abruptly from 5 to 14 weeks in both muscles, but no difference between muscle types was detected. 3. The cell size of the endomysial honeycombs increased with the development of myofibres, and the mesh size of the perimysium around the honeycombs enlarged. 4. In both muscles endomysia were an incomplete network of collagen fibrils with many foramina at one week, became a very thin membrane of felt-like fabric in 2 to 5 weeks and thereafter increased in thickness until 11 to 14 weeks. 5. Perimysial width around the secondary fasciculus differed between the muscle types after 5 weeks. In the wider perimysium of ITL muscle, the collagen fibres increased in number and size to make a stack of collagen bands around the fasciculus. In the narrower perimysium of PT muscle, a few platelets of collagen fibres also developed. 6. The perimysial collagen fibre at 1 to 2 weeks had a smooth surface and appeared to be composed of fine collagen fibrils. The fibre at 11 to 14 weeks showed a rugged surface and was composed of coarser collagen bundles that combined with each other into a net-like configuration with very slim meshes. 7. Our results showed that the collagenous components of chicken intramuscular connective tissue changed markedly during the early period of muscle growth in distribution, architecture and quality but with little difference in quantity.     

Comparison of the histological and histochemical properties of skeletal muscles between carbon dioxide and electrically stunned chickens

1. Histological and histochemical profiles of Musculus pectoralis (PT, type IIB fibres), M. iliotibialis lateralis (ITL, types IIA + IIB fibres) and M. puboischiofemoralis pars medialis (PIF, type I fibres) were compared in carbon dioxide (37%, 70 s) and electrically (14 V, 5 s) stunned male chickens. 2. Muscle materials were taken at 0, 4 and 24 h from carcases dressed and cooled with ice-water mixture for 30 min. Glycogen and fat contents, and adenosine triphosphatase and reduced nicotinamide adenine dinucleotide dehydrogenase activities of fibres were measured. 3. In PT muscle at 0 h, gas stunned chickens showed many fibres with high glycogen content but those electrically stunned contained few such fibres. Fibres from gas stunned birds had lost almost all their glycogen after 24 h of cold storage. 4. In the ITL muscle of gas stunned chickens at 0 h residual glycogen was observed in type IIB fibres. In contrast, in the electrically stunned birds it was in type IIA, showing the different effects of the stunning methods. During cold storage, glycogen disappeared earlier in type IIB than IIA fibres. 5. In PIF muscle with fibres of low glycogen content, the gas stunned chickens maintained a good fibre structure for 4 h or more, but the electrically stunned had already lost intact fibre structure at 4 h. 6. These results indicated that the carbon dioxide stunning was a better method for chicken welfare and meat quality than electrical stunning.     

Effects of divergent selection for body weight on three skeletal muscles characteristics in the chicken

1. Histochemical (fibre type distribution and areas) and biochemical (myosin isoforms) characteristics of three muscles, M. anterior latissimus dorsi, M. pectoralis major and M. sartorius, were compared among male chickens of two lines at 11 and 55 weeks of age.

2. The lines were derived from a divergent selection based on growth rate. Cockerels from the Fast Growing Line (FGL) were 2^‐3 times heavier than those from the Slow Growing line (SGL) when 11 weeks old and 1–7 times at 55 weeks of age. The latter age was chosen as representative of the adult stage and the 11‐week age because, at this time, FGL cocks weighed as much as SGL cockerels at 55 weeks.

3. At both ages, the two lines showed similar fibre type distributions, but the total number in the ALD muscle, and the size (cross‐sectional areas) of fibres in each muscle were higher in the FGL compared with the SGL (14–6% and 33% more at 11 and 55 weeks of age respectively in favour of the FGL birds).

4. The two lines displayed similar myosin isoform patterns when adult muscles were compared (55 weeks). They differed slightly at 11 weeks of age, muscle differentiation being completed only in the FGL.

5 Comparisons of the two lines at the same live weight (i.e. FGL cockerels at 11 weeks of age and SGL cockerels at 55 weeks) showed larger muscle fibres in the SGL and no difference in the isomyosin patterns.     

Fibre structure and metabolites in M. longissimus dorsi of Wild Boar, Pietrain and Meishan pigs as well as their crossbred generations

Fibre traits and glycolytic metabolites in musculus longissimus dorsi of European Wild Boar, Pietrain and Meishan as well as their F₁ and F₂ crossbred generations were evaluated and compared. Pietrain had the highest relative number of white fibres and the largest muscle fibres. Wild Boar showed the smallest muscle fibres. The R -value and lactate level of Wild Boar and Meishan were low, whereas Pietrain had high R -values and lactate levels. The glycogen level was highest in Wild Boar and lowest in Meishan. The F₁- and F₂-crossbreds often had trait values between those of their founder breeds. Several antagonistic relations between fibre characteristics, muscle metabolites and performance traits for carcass and meat quality have been found. They are family-specific and strongest within the crossbreds of the Pietrain-based families.     

Histochemical properties of muscle fibres types and enzyme activities in skeletal muscles of Standardbred trotters of different ages

Fibre characteristics and enzyme activities were determined for the gluteus, semitendinosus, vastus lateralis and triceps brachii muscles of 55 Standardbred trotters of different ages. Four fibre types (I, IIA, IIB, IIC) were demonstrated by histochemical staining of myofibrillar adenosine triphosphatase after preincubation at different pH values. Type II fibres predominated in all the muscles and the type IIA/IIB ratio was higher in horses over 5 years than in younger horses, except in the vastus in which the IIA/IIB ratio did not change with age. The vastus had the highest proportion of type IIA fibres and the semitendinosus the highest proportion of type IIB fibres. Histochemical demonstration of NADH dehydrogenase disclosed that almost 100 per cent of the type IIA and many of the type I and IIB fibres were medium-stained; the remaining type I fibres were darkly stained and the type IIB fibres lightly stained. In older horses more fibres were stained for NADH dehydrogenase. The activity of triosephosphate dehydrogenase decreased that that of 3-hydroxy-acyl-coA dehydrogenase and citrate synthase increased in all the muscles except the vastus with increasing age. The greatest increase in oxidative capacity occurred in the gluteus and triceps. Training, rather than age, was regarded as the factor inducing these changes. The results emphasise that histochemical data are only semiquantitative, and there are apparent discrepancies in the intensities of histochemical staining and the biochemical evaluation of various enzymes.     

Muscle fibre distribution in forelimb,hindlimb and trunk muscles in three bat species: The little Japanese horseshoe,greater horseshoe and Egyptian fruit

This study characterised muscle fibres in trunk, forelimb and hindlimb muscles of three bat species: little Japanese horseshoe (Rhinolophus cornutus), greater horseshoe (Rhinolophus ferrumequinum) and Egyptian fruit (Rousettus aegyptiacus). Twenty-seven muscles from trunk, forelimb and hindlimb were dissected, weighed and analysed by immunohistochemistry and sodium didecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) and determined their cross-sectional areas (CSA). Results showed that Type IIa and Type IIa/x made the highest proportion of total muscle mass. Moderate proportion was formed by Type IIb. Type I and IIx appeared at very low levels in all bats. Type IIb was the only fibre type detected in patagial muscles in wing membrane of greater horseshoe while other fibre types were not observed. Type I muscle fibres were very few and appeared infrequently in fifteen muscles of Egyptian fruit and in only one muscle in each, greater horseshoe and little Japanese horseshoe. Type IIx was also detected in three muscles in greater horseshoe and only one muscle in Egyptian fruit but none in little Japanese horseshoe. The highest average CSA μm² was detected in Type IIb and values were 734.2μm² for LHB; 1537.9μm² for GHB and 1,720.9μm² for EFB. Lowest and undetermined values were observed for Type I and IIx. These data demonstrate that Type IIa, IIa/x and IIb form significant proportion of adult bat muscle mass and Type IIb is the largest fibre type. The distribution pattern is suggestive of specialised functions of the fibres in relation to orientation and speed of bats during flight.     

The Post-larval Development of Lateral Musculature in Gilthead Sea Bream Sparus aurata (L.) and Sea Bass Dicentrarchus labrax (L.)

Fibre-type differentiation of lateral musculature has been studied in gilthead sea bream Sparus aurata (L.) and sea bass Dicentrarchus labrax (L.) during post-larval development using ultrastructural, histochemical and morphometric techniques. The study showed three muscle layers: red, intermediate (or pink) and white. Initially, most of the red muscle showed low myosin ATPase (m-ATPase) activity fibres, whereas near the transverse septum some small high m-ATPase activity fibres appeared and later acquired a rosette aspect. Afterwards, during adult growth the red muscle showed a histochemical mosaic appearance. The pink muscle in sea bass was observed at the beginning of juvenile development by the oxidative technique (NADH-RT reaction) whereas in gilthead sea bream it was also observed at the end of larval development. The pink layer consists of high m-ATPase activity fibres. However, along the muscle development other low and moderate m-ATPase activity fibres were observed close to the red and white muscles, respectively. The white muscle of juvenile fish showed a histochemical mosaic appearance near the pink muscle. In adult specimens the mosaic white muscle spread out occupying the whole of the myotome. Morphometric analysis shows a significant increase in mean fibre diameter during post-larval development, as shown by the Student's t-test (hypertrophic growth). Skewness and kurtosis values of fibre diameters point to the generation of a new fibres from the myosatellite cells (hyperplastic growth).     

Energy metabolism in relation to skeletal muscle fibre properties during treadmill exercise

The skeletal muscle metabolism of horses with a wide range of cardiocirculatory capacities was studied during a standardised near-maximal exercise test in relation to muscle fibre composition. Although the same amount of work was performed by all horses the amount of triglycerides and glycogen utilised and lactate accumulated differed widely. Both blood and muscle lactate accumulation were positively related to the amount of glycogen utilised. These factors were in turn positively associated with the percentage of Type IIB fibres and consequently negatively associated with the percentage of Type IIA fibres. The percentage of Type IIB fibres was negatively correlated to the activities of the oxidative enzymes citrate synthase and 3-hydroxyacyl-CoA-dehydrogenase and positively associated with the lactate dehydrogenase activity. The results indicate that the horses with a high proportion of Type IIB fibres had a lower muscle oxidative capacity and were, therefore, for energy production, more dependent upon glycolysis with subsequent lactate accumulation than horses which had a high proportion of Type IIA fibres. The different metabolic properties of the muscle fibre types indicate that the pattern of muscle fibre recruitment could have a significant effect on intramuscular substrate utilisation.     

Effects of preservation method and beta-glucanase supplementation on ileal amino acid digestibility and feeding value of barley for poultry.

1. Effects of preservation method (drying or air-tight storage of whole grain and ensiling of rolled high-moisture grain) and beta-glucanase supplementation (Econase) on apparent ileal amino acid digestibilities and metabolisable energy content of barley were evaluated with Ross broiler chickens. In addition, the effect of barley preservation method was assessed using Leghorn cockerels. 2. Birds were given either a semi-purified soyabean meal basal diet or a mixture of the basal diet and barley (50:50 on dry matter basis). Apparent ileal digestibilities (AID) of nutrients were assessed using the slaughter technique. AID of nutrients and nutrient digestibility measured using excreta (AED) were determined using chromium mordanted straw as an indigestible marker. 3. In broilers, AID of amino acids, dry matter and organic matter were lower for dried than air-tight stored barley, particularly for diets based on ensiled barley. In cockerels, barley preservation method had no effect on amino acid AID. The AED of nutrients and nitrogen corrected apparent metabolisable energy content (AMEn) was highest for ensiled barley across both experiments. 4. beta-glucanase supplementation increased nutrient digestibility, phosphorus retention and AMEn content of air-tight stored and dried barley diets in particular but had only negligible effects on ensiled barley. Beta-glucanase improved the AID of amino acids in dried barley but not in air-tight stored or ensiled barley. 5. Amino acid digestibilities were lower in broilers than cockerels and the effect of barley preservation on feeding value of barley was different for broilers and cockerels.     

Proportions of melanocyte stimulating hormone-immunoreactive cells in the adenohypophysis of Silky fowl and hyperpigmentation-free cockerels

Alpha‐melanocyte stimulating hormone (α‐MSH) is one of the main regulators for melanocytes, and the adenohypophysis is one of the major tissues for the synthesis of this hormone. The Silky fowl is a characteristic breed of chicken with hyperpigmentation throughout the body. The involvement of the adenohypophysis in the hyperpigmentation of this breed is not known. In the present study, the proportion of melanocyte stimulating hormone‐immunopositive cells (MSH cells) in the adenohypophysis was immunocytochemically compared between Silky, Red Cornish × New Hampshire (RN) crossbred and Japanese bantam cockerels at 15 weeks of age. After the body and gland were weighed, the adenohypophyseal cells were enzymatically dispersed and immunostained for α‐MSH, and the immunopositive MSH cells were counted. The weights of the body and adenohypophysis were heaviest in the RN crossbred, followed by the Silky and lightest in the bantam cockerels. In contrast, the ratio between adenohypophysis and bodyweight was much larger in the Silky and the bantam than in the RN crossbreed (P < 0.05). The population of MSH cells in the adenohypophysis was larger in the Silky (14.3%) than in the RN crossbreed (8.0%) and the bantam (8.1%) cockerels (P < 0.05). From these results, it was concluded that prepubertal Silky cockerel have numerous MSH cells in the adenohypophysis suggesting a relationship to hyperpigmentation.     

The effect of testosterone on gastrocnemius muscle fibres in growing and adult male and female rats: a histochemical,morphometric and ultrastructural study

In this study, the effect of testosterone on gastrocnemius muscle fibres in growing and adult rats (male and female) was examined using histochemical, morphometric and ultrastructural techniques. After physiological saline (PS), olive oil (OvO) or olive oil + testosterone (OvOT) injections on 72 rats (growing and mature, 36 male and 36 female), the sample tissues of fibre types of the gastrocnemius muscle taken were examined by histochemical [alkaline adenosine triphosphatase (alk-ATPase), acid ATPase (ac-ATPase)], morphometric and ultrastructural techniques. In PS-injected control groups, the gastrocnemius muscle of both sexes contained all the fibre types studied [slow-oxidative muscle fibres (type I), fast-oxidative glycolytic muscle fibres (type IIA) and fast-glycolytic muscle fibres (type IIB)]. The type I fibres had the smallest diameter, type IIA had a medium diameter and type IIB fibres had the largest diameter. In OvO-injected groups, it was observed that the OvO had little effect on the gastrocnemius muscles of either sex, although there was significant enlargement of type IIB fibres. After the injection of OvOT, hypertrophy of muscle fibres was determined by morphometric study. The biggest increase in diameter was on type I fibres. In addition, degenerations on some mitochondria, accumulation of lipid droplets on type I and type II fibres, an increase in glycogen particles, bifurcation of myofibrils, an increase in the number and diameter of units resembling T tubules and an increase in ribosomal content were also observed in the same group by transmission electron microscope. Consequently, it was determined that testosterone can induce protein synthesis in gastrocnemius muscle fibres, and induces changes in shape and size, and also can change the appearance and the number of fibres.     

蛋公鸡强饲法评估非淀粉多糖酶对肉仔鸡日粮表观代谢能值的作用效果

以 2 4 0只艾维茵肉仔鸡和 2 4只海兰褐成年蛋公鸡为试验动物 ,通过代谢试验研究非淀粉多糖酶对肉仔鸡和成年蛋公鸡能量利用的作用效果。试验结果表明 :在含有 1.8%小麦总戊聚糖、0 .2 %可溶性小麦戊聚糖的日粮中添加酶制剂对肉仔鸡的生产性能影响不显著 (P >0 .0 5 )。三种饲用酶制剂显著影响 3周龄肉仔鸡的能量利用 ,分别提高日粮表观代谢能值 (AME) 3.5 % ,4 .9% ,3.5 % (P =0 .0 2 9,0 .0 0 4 ,0 .0 2 3)。通过回归方程 (AME3周龄肉仔鸡 =1.16 0×AME蛋公鸡 - 1.30 9,R2 =0 .989,P =0 .0 0 6 ) ,可以成年蛋公鸡为模型 ,采用排空强饲法快速评估酶制剂对 3周龄肉仔鸡日粮表观代谢能值的影响。