Effects of nutritional level on muscle development, histochemical properties of myofibre and collagen architecture in the pectoralis muscle of male broilers

1. The effects of nutritional level on muscle development, histochemical properties of myofibre and collagen architecture in the pectoralis muscle were evaluated using male broilers of Red Cornish x New Hampshire stock, reared on diets of high nutritional value for up to 80 d (H80d) and low nutritional value for up to 80 d (L80d, same age as H80d) or 95 d (L95d, same body weight as H80d). 2. The total live weight and the weight of pectoralis muscle were lower in L80d than in both H80d and L95d. The muscle weight as a percentage of live weight was 8.7% in L80d, 10.7% in H80d and 11.5% in L95d. 3. Pectoralis muscle was composed only of type IIB myofibres and showed no differences in myofibre type composition among the chicken groups. The largest diameter of type IIB myofibres was observed in L95d, followed by H80d and the smallest in L80d. 4. The total amount of intramuscular collagen did not differ among the chicken groups (1.92 to 1.99 mg/g). Types I and III collagens were immunohistochemically detected in both the perimysia and endomysia. The thin perimysia around the primary myofibre fascicles showed larger width in H80d than L80d and L95d, and also the thick perimysia around the secondary fascicles in H80d than L80d. 5. The collagen structure of the perimysium was most developed in H80d, followed by L95d and on the least in L80d. The development of perimysial collagen fibres could be enhanced by a rapid growth rate of the muscle induced by high nutritional level and depressed by a slow growth rate with low nutritional foods. 6. The endomysial collagen architecture was observed as a felt-like tissue of the fibril bundles with many slits. The thinnest endomysial wall was observed in L80d, followed by H80d and the thickest in L95d. 7. From these results, it was indicated that foods of high nutritional value could enhance growth of the pectoralis muscle of broilers, and this is accompanied by hypertrophy of the type IIB myofibres and development of the perimysial collagen architecture.     

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.     

Comparison of collagen content, distribution and architecture among the pectoralis, iliotibialis lateralis and puboischiofemoralis muscles with different myofiber composition in Silky cocks

The total amount of collagen, the relative distributions of types I and III collagens in perimysium and endomysium, and the collagen fiber architecture were compared among the pectoralis (PT), iliotibialis lateralis (ITL) and puboischiofemoralis (PIF) muscles in Silky cocks. All of the myofibers in the PT muscle were type IIB, the myofibers in the ITL muscle were divided into type IIA, 41.7% and IIB, 58.3%, and the PIF muscle was composed of type I, 24.6%; IIA, 64.6%; and transitional, 10.8%. The total amount of collagen differed significantly among the PT (2.92 mg/g), PIF (4.20 mg/g) and ITL (8.06 mg/g) material, where only the PIF was a whole muscle with epimysium. On the image analysis of the immunohistochemical preparations, the percentage area of perimysial collagen to the total area in each type differed significantly among the PIF, PT and ITL muscles, where it was 26.8, 50.0 and 74.4% for the type I collagen and 27.4, 32.9 and 61.7% for the type III collagen, respectively. In the scanning electron micrography of the perimysium in macerated preparations, thick bundles of collagen fibers were observed in the ITL muscle, thinner but broad platelets in the PT muscle, and a coarse tissue of thinner collagen fibers in the PIF muscle. However, the endomysial fabric of collagen fibrils was similar among the muscles. Small, transverse collagen fibers, which branched off from the thicker perimysia, occupied narrow interendomysial spaces and separated the primary myofiber fasciculi. The results indicate that the ITL muscle, localized in the distorted and overextended part of the leg and subject to strong external forces, had highly developed perimysial collagen fiber bundles, but the ITL endomysial collagen architecture was similar to that of the PT and PIF muscles.     

早期数量限饲对肉仔鸡生长性能和胴体特性的影响

试验研究了早期数量限饲对肉仔鸡生长性能和胴体品质的影响。200只8日龄艾维茵肉仔鸡被随机分成4组,每组五个重复,每重复10只鸡。对照组基础饲粮根据NRC营养水平配制,试验组肉仔鸡从8日龄开始喂料量分别为对照组的90%、80%和70%,限饲1周后各组恢复自由采食。试验结果表明:在第2周,限饲各组肉仔鸡的体重和日增重分别显著低于对照组(P<0.05);在第3周,限饲90%组完成补偿生长,体重与对照组差异不显著(P>0.05);在第4周,限饲80%和70%组完成补偿生长,体重与对照组差异不显著(P>0.05);5、6、7周及2～7周各组在体重、日增重、日采食量和饲料转化率等方面都无显著差异(P>0.05)。早期数量限饲对肉仔鸡胴体特性没有显著影响(P>0.05)。     

Effects of rice feeding and carnitine addition on growth performance and mRNA expression of protein metabolism‐related genes in broiler grower chicks

This study was carried out to evaluate the nutritional effects of rice feeding and carnitine addition to a diet for broiler chicks. Thirty‐six male 10‐day‐old broiler chicks were assigned to one of the following four treatment groups: corn‐based diet (corn group), rice‐based diet (rice group), and each diet with added carnitine (100 ppm). The experimental period was 2 weeks. Rice feeding resulted in significantly higher growth performance (body weight gain and feed efficiency) compared to corn feeding. Carnitine addition also resulted in higher growth performance. Breast muscle and thigh muscle weight (g) were significantly higher in broiler chicks fed rice and those fed diets with added carnitine. Liver mRNA expression of IGF‐I was significantly higher in broiler chicks fed rice compared to those fed corn. There was no significant difference in mRNA expression of muscle atrogin‐1 or liver CPT‐I between broiler chicks fed rice and those fed corn, not between broilers chicks fed diets containing carnitine or not. Overall, these results show that rice feeding and carnitine addition improve the growth performance of broiler chicks by increasing mRNA expression of liver IGF‐I. In addition, carnitine action is not affected by different cereals (corn and rice).     

肉鸡补偿生长技术研究进展

对肉鸡进行补偿生长处理,可降低其死淘率、改善饲料效率,并且不影响其上市活重或净膛重,但遗传(血统)、性别、限饲养分的时期和时间、限饲程度以及恢复饲喂常规饲料时间长短会影响补偿生长效果。本文综述了可用于肉鸡补偿性生长的各种方法和参数,同时归纳了补偿生长的机制。     

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.     

Effects of growth rate and compensatory growth on body composition in lambs

Fifty lambs were used in a comparative slaughter experiment to determine the effects of growth rates and compensatory growth on body composition. The study consisted of a growing and a finishing phase. During the growing phase, lambs (20 to 30 kg) were fed three different concentrate levels (30, 50 or 70%) to gain at three different rates (slow, medium and rapid). The finishing phase was evaluated in two periods (early, 30 to 38 kg; late, 38 to 45 kg). All lambs received 70% concentrate diets during the finishing phase. Groups of five lambs were sacrificed at 20, 30, 38 and 45 kg fleece-free weights for whole-body chemical analysis. At 30 kg live weight, lambs on a rapid growth diet were the fattest (P less than .01) and contained the least protein (P less than .05) in their empty bodies. The slower the lambs gained during the growing phase, the greater (P less than .05) was the response in rate of gain and feed efficiency during both periods of the finishing phase. Compensatory growth occurred in two stages; a greater proportion of protein gain was made early while a greater proportion of the fat gain was made during the late period of the finishing phase.     

The efficiency of nitrogen retention during compensatory growth of food-restricted broilers

1. Two experiments were conducted to investigate the influence of compensatory growth, induced by early quantitative food restrictions, on the efficiency of nitrogen-retention in two lines of Ross broilers. 2 . Birds were restricted to 80% of the ad libitum intake of the previous 24 h of the control group from d 4 to d 7. After the period of restrictions all birds were fed ad libitum . 3 . In both trials, the final body weight of the restricted Ross 208(308) birds was similar or even higher than that of the control group. For the Ross 508 line, compensatory growth was substantial in the first trial, but non-existent in the second trial. In all cases, the mortality of restricted birds was lower than in control birds. 4. Not only environmental factors, but mainly chick quality, seemed to have a major influence on the capacity of the chickens to establish compensatory growth. 5. As compensatory growth was established, some improvement in N retention was induced. Although differences were not significant, they may be environmentally important. 6. It is concluded that a retardation of the early growth of fast growing broiler chickens can, in certain circumstances, reduce mortality and increase performance and N retention.     

噪声对AA鸡生长发育的影响

本试验探讨了噪声对AA鸡生长以及血液生理生化指标的影响。供试鸡为100只15日龄的AA鸡，把其按交叉分组法分为四组（1个对照组和3个试验组），对照组不给噪声，试验组（A、B、C）组分别给予70分贝、80分贝、90分贝的噪声，试验期为30天。结果表明，噪声能引起：增重显著减缓，90分贝组鸡增重与对照组差异显著；屠宰率、全净膛率显著降低，80分贝，90分贝组屠宰率与对照组差异显著，90分贝组全净膛率与对照组差异显著：甲状腺素浓度A、B、C组与对照组相比，依次降低，且试验组与对照组差异显著。     

Single injection of clenbuterol into newly hatched chicks decreases abdominal fat pad weight in growing broiler chickens

The aim of the current study was to examine the effects of clenbuterol injection into newly hatched chicks on both the abdominal fat pad tissue weight and the skeletal muscle weight during subsequent growth. Twenty‐seven 1‐day‐old chicks were divided into two groups, receiving either a single intraperitoneal (i.p.) injection of clenbuterol (0.1 mg/kg body weight) or phosphate‐buffered saline (PBS). Body weight gain, feed intake and feed conversion ratio were not affected by clenbuterol injection during the 5‐week experimental period, while the abdominal fat pad tissue weight of the clenbuterol‐injected chicks was lower than that of the control chicks at 5 weeks post‐injection. Plasma non‐esterified fatty acid concentrations were significantly increased in the clenbuterol‐injected chicks, while plasma triacylglycerol concentrations did not differ. Additionally, the enzymatic activity of fatty acid synthase was lower in the liver of the clenbuterol‐injected chicks. Conversely, the skeletal muscle weights were not affected by clenbuterol injection. These results suggest that a single clenbuterol injection into 1‐day‐old chicks decreases the abdominal fat pad tissue weight, but may not affect skeletal muscle weights during growth. © 2015 Japanese Society of Animal Science     

Effect of low doses of dietary rare earth elements on growth performance of broilers

The present study was designed to investigate effect of dietary rare earth elements (REE), including both organic and inorganic compounds, on growth performance of broilers. In experiment 1, a total of 180 male Ross broiler chicks were allocated to 72 pens with different assignment: four chicks per pen or individually. The following three treatment diets were applied: control, REE‐chlorides at a dose of 40 mg/kg and REE‐citrate at a dose of 70 mg/kg. Each treatment group had 24 pens containing both assignments (12 pens each). In experiment 2, a total of 72 male 3‐day‐old Ross broiler chicks were separated to four groups: control, REE‐chlorides at a dose of 70 mg/kg and REE‐citrate at doses of 70 mg/kg and 100 mg/kg. In experiment 1, dietary REE‐citrate improved body weight gain during the overall period by 5.0% (p < 0.05) while the increase with REE‐chloride was not significant. In experiment 2, growth effects (p < 0.05) were only found in the period from day 21 to slaughter with all REE forms, and feed conversion ratio was improved by 3.4% (p < 0.05) with REE‐citrate. No significant effects of REE were found on chill weight, percentages of breast meat, thigh weight, drumstick weight and wing weight. Concentrations of La and Ce in the liver and muscles were very low, accounting for 0.11–0.76 and 0.02–0.30 mg/kg respectively. There was weak tendency for a dose–response relationship especially in the groups supplemented with REE‐chlorides. The main blood serum biochemical parameters were not significantly affected by REE in the diets. The results suggest that dietary supplementation of low doses of REE‐citrates might improve growth performance of broilers without affecting carcass composition and health of the broilers.     

Responses to heat stress in commercial and local broiler stocks. 2. Developmental stability of bilateral traits.

1. Developmental stability of bilaterally symmetrical traits was measured in two fast (G1 and G2) and one slower growing (G3) broiler stocks when conditioned (chicks exposed to 36 degrees C for 24 h at 5 d of age) or food restricted (food withdrawn 2 h before the hot period and chicks fed between 17.00 and 08.00 h) during heat stress administered daily from 28 to 49 d of age. 2. Length of face, length, width and weight of shanks, weights of P. major and P. minor muscles, and weights of lung and caeca were chosen as bilateral traits representative of skeletal, muscle, respiratory and digestive systems. 3. Development of skeletal bilateral traits was affected primarily by genotype and sex. The heart:lung ratio decreased with conditioning in stocks G1 and G2 at 21 d. Face length, shank length and shank weight exhibited antisymmetry, whereas shank width and weights of P. minor, lung and caeca exhibited fluctuating asymmetry and antisymmetry. For P. major weight, there was directional asymmetry. 4. In general, relative asymmetry of skeletal traits was lower than for traits associated with muscle and with respiratory and digestive systems. Relative asymmetry of P. major weight was lower in conditioned and G3 broilers than in their respective counterparts. 5. If relative asymmetry is a valid indicator, item heat stress may be less in slower growing and conditioned broilers.     

早期限饲对肉鸡肺动脉高压综合征发病率、生产性能和腹脂率的影响

采用低温诱发肉鸡肺动脉高压综合征,对比观察不同的早期限饲方法对于常温和低温条件下PHS的发病率、肉鸡生产性能和腹脂率的影响。在试验1中,限饲处理组肉鸡分别于7￣14日龄或7￣21日龄每天给料8h,对照组肉鸡全程自由采食。在试验2中,限饲组肉鸡分别于7￣14日龄给予对照组肉鸡前1d饲料消耗量的60%或80%。结果表明:早期限饲能够降低肉鸡PHS的发病率,在低温条件下尤其明显;早期限饲改善了饲料效率,同时未对肉鸡的胴体品质产生显著的影响,且适当限饲不影响肉鸡的最终上市体重。这表明早期限饲是一种有效的控制肉鸡PHS的方法,值得在实际生产中推广应用。     

Comparison of collagen fibre architecture between slow-twitch cranial and fast-twitch caudal parts of broiler M. latissimus dorsi

1. Collagen fibre architectures of perimysium and endomysium in the slow-twitch cranial and fast-twitch caudal parts of broiler M. latissimus dorsi were compared. 2. Type I and III collagens were distributed in both perimysium and endomysium as indicated by their positive immunohistochemical reactions to polyclonal antibodies. 3. Cells invested by endomysium with no myofibres were larger in the cranial part because of the presence of larger slow-twitch myofibres. The honeycomb structure of endomysium was divided into several parts by thick perimysium. 4. The thick perimysial collagen fibres with parallel fibrils, which were interconnected by the loose reticular fibrils and thin fibres, were more numerous and thicker in the cranial part than the caudal. 5. Thick endomysial sidewall of cells in the cranial part was composed of a rougher reticulum of slightly thicker collagen fibrils compared with the thin sidewall in the caudal part. 6. These results indicated that both perimysial constitutions of collagen fibres and endomysial collagen fibrils had attained much larger growth in the slow-twitch cranial part than the fast-twitch caudal in broiler latissimus dorsi muscle.     

Supplementation of graded levels of organic zinc in the diets of female broilers: effects on performance and carcase quality

Zinc is an essential trace element. The objective of this research was to investigate the effects of various levels of organic zinc (OZ) supplementation on growth performance and carcase quality of female broiler chickens. A total of 3200 1-d-old female broiler chicks were randomly allotted to 16 floor pens with 200 birds per pen. A maize-wheat-soyabean meal basal diet (Control) was formulated and 20 mg/kg OZ (20 OZ), 40 mg/kg OZ (40 OZ), and 80 mg/kg OZ (80 OZ) were added to the basal diet to form 4 dietary treatments with 4 replicates per treatment. The OZ source was zinc proteinate which contained 15% zinc. Results showed no significant difference between the treatments in growth performance. A significant increase in thigh skin epidermis and dermis thickness was shown in the OZ supplementation groups; however, no effect was found on the thickness of back skin epidermis and dermis. Collagen contents in breast and thigh meats were not influenced by OZ supplementation but a significant increase in collagen content was found in the back and thigh skin. This increase in collagen content was significantly greater in the back and thigh skin of OZ 80 than with OZ 20. Shear force value and zinc concentration in skins and meat were not significantly influenced by supplementation with OZ. It is concluded that dietary OZ does not improve growth performance of broilers; however, it could increase skin thickness by increasing collagen content in skin, thereby improving carcase quality.     

羽速基因对莱芜黑鸡早期生长速度和蛋用性能的影响

试验选用1日龄健康雏鸡,根据羽毛生长速度进行快慢羽分群饲养,研究羽速基因对莱芜黑鸡早期生长速度和蛋用性能的影响,结果表明,羽速基因对早期生长速度有一定的影响,初生重、2、4、7、10周末快羽系鸡体重显著高于慢羽,但对蛋用性能方面影响差异不显著。     

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.     

Evaluation of effects of the dry‐heat‐processed sweet potato waste as broiler feed

This study was conducted to examine the effects of feeding dry‐processed sweet potato waste on the growth of broilers. Sweet potato waste was air‐dried (A‐SPW) or heat‐dried (D‐SPW). Twenty‐four 14‐d‐old chicks were assigned to the following groups (14–28 days): control, fed a corn‐soybean meal‐based diet; A‐SPW, fed the basal diet with 55% of the corn replaced with A‐SPW meal; D‐SPW, fed the basal diet with 50% of the corn replaced with D‐SPW meal. The feed conversion ratio (feed/gain) of the D‐SPW group was greater than that of the A‐SPW group. The relative weight of abdominal fat and the muscle lipid content of the D‐SPW group were increased compared with those of the A‐SPW group. The metabolizabilities of crude protein and gross energy of the D‐SPW group were increased compared with those of the A‐SPW group. The plasma α‐tocopherol concentrations of the A‐SPW and D‐SPW groups were greater than that of the control group. Plasma malondialdehyde was decreased in the A‐SPW and D‐SPW groups, and muscle malondialdehyde was decreased in the D‐SPW group, compared with the control group. Our results demonstrate that dry‐heat processing improves the nutrient metabolizability of sweet potato waste and makes it into available feed for broilers.     

Effect of breeder vaccination on immunization of progeny against Newcastle disease

Two experiments were conducted to determine the effect of breeder vaccination program and maternal antibody on the efficacy of Newcastle disease immunization of 1-day-old chicks. Experimental protocol was the same for both. In the first experiment, broilers were from breeders that were 32 weeks old, and in the second experiment, broilers were from breeders 50 weeks old. Breeders received three live Newcastle disease virus (NDV) vaccines and either a killed vaccine at 18 weeks or continual live boosting at 60-to-70-day intervals through lay. Broilers were vaccinated at 1 day of age with a commercial coarse-spray machine; they were bled, sera were examined for antibody against NDV, and broilers were challenged with virulent NDV at 2, 4, and 6 weeks of age. In the first experiment, maternal antibody was higher in chicks from the younger breeders given the inactivated vaccine, and in the second experiment maternal antibody was higher in chicks from older breeders given continual live vaccines. Higher antibody in 1-day-old broilers resulted in fewer vaccine-induced reactions, less vaccine virus shed, and decreased duration of vaccine-induced immunity from coarse-spray vaccination.