Response time of broiler chickens to cimaterol: meat tenderness, muscle composition fiber size, and carcass characteristics

Radix Puerarin Extract (Puerarin) Could Improve Meat Quality of Heat-Stressed Beef Cattle Through Changing Muscle Antioxidant Ability and Fiber Characteristics

The experiment was conducted to investigate the effects of dietary supplementation with Puerarin on meat quality, muscle antioxidant ability, and muscle fiber characteristics of beef cattle under a hot environment in summer. Thirty-two 15 ± 1.5-month-old Jinjiang bulls (291.65 ± 8.84 kg) were randomly divided into four groups with dietary Puerarin at 0 (control), 200 (Pue200), 400 (Pue400), and 800 (Pue800) mg/kg in the feed concentrate (n = 8). The feeding trial lasted for 60 days after a 10-day adaptation period (July 1-September 8); the average values of temperature, relative humidity and temperature, and humidity index were 30.68°C, 68.05%, and 81.81, respectively. The growth performance on day 40 of the experiment period was calculated. After 60 days' experimental period, four Jinjiang cattle per treatment from the control group, Pue400 group, and Pue800 group were slaughtered. Compared with the control group, the Pue400 and Pue800 groups improved the growth performance of beef cattle; the Pue800 group elevated the activities of superoxide dismutase, total antioxidant capacity, and glutathione peroxidase in the M. longissimus thoracis (LT) muscle. In the control group, the cell membrane was incomplete, and most of the mitochondria were elongated and in a fission state, while in the Pue400 and Pue800 groups, the cell membrane was clear and complete, and the mitochondria presented with round and oval shapes. Compared with the control group, the Pue400 and Pue800 groups reduced the shear force of the LT muscle, and the Pue400 group decreased the muscle fiber diameter and the myosin heavy-chain (MyHC)-IIb gene expression. Furthermore, the Pue400 and Pue800 groups decreased the ratio of AMP/ATP, the Pue800 group reduced the AMP-activated protein kinase α2 mRNA expression, and the Pue400 group improved the nuclear respiratory factor 1 mRNA expression. These results indicated that dietary supplementation with Puerarin might be beneficial to the meat quality of heat-stressed beef cattle by improving muscle antioxidant ability and reducing the MyHC-IIb muscle fiber composition. Based on the results of this study, we recommended 400 mg/kg Puerarin in the feed concentrate of beef cattle (~300 kg) for mitigation of heat stress.

Enterococcus faecium NCIMB 10415 supplementation improves the meat quality and antioxidant capacity of muscle of broilers

The present study was conducted to investigate the effects of Enterococcus faecium (E. faecium) on the meat quality and antioxidant capacity of muscle in broilers. A total of 600 Arbor Acre broiler chickens (1-day-old, male) were randomly divided into five treatments with six replicates (20 chickens per replicate) for each treatment. The five treatments were the control treatment (CON, basal diet), antibiotic treatment (ANT, basal diet supplemented with 0.1% chlortetracycline) and E. faecium-supplemented treatments (LEF, MEF and HEF, basal diet supplemented with 50, 100 and 200 mg/kg of E. faecium respectively). The experiment lasted 42 days in two periods of 21 days. Results showed that there were no differences in breast meat quality among different treatments (p > 0.05). Compared with the CON and ANT treatments, the yellowness of thigh meat in E. faecium-supplemented treatments was significantly increased (p < 0.05); the shear force of thigh meat in the LEF and MEF treatments was lower than that of the CON treatment (p < 0.05). In addition, the concentration of the inosine monophosphate (IMP) in the breast and thigh meat of the MEF treatment was significantly higher than that of the other treatments (p < 0.05). At 21 days, the total antioxidant capability (T-AOC) level and glutathione peroxidase (GSH-Px) activity of breast meat and superoxide dismutase (SOD) in the thigh meat of the MEF treatment were greatly increased (p < 0.05). At 42 days of age, the catalase (CAT), GSH-Px and T-AOC activities in the breast meat of the MEF treatment were increased (p < 0.05) and the CAT activity of thigh meat in the LEF and MEF treatments was increased (p < 0.05). In conclusion, E. faecium supplementation increased the meat quality of the thigh muscle, increased the IMP content and the activities of CAT, SOD, T-AOC, and GSH-Px of muscle in broilers. Supplementation with 100 mg/kg E. faecium had the greatest effects.

Effect of hybridization on carcass traits and meat quality of erlang mountainous chickens

Native chickens hold a significant share of the market in China. In response to the huge demand from the market, the productivity of Chinese native chickens needs to be improved. Cross breeding is an effective method to increase productivity, although it might affect meat quality. In this study, two pure lines (SD02 and SD03) of Erlang mountainous chickens were hybridized with a yellow feather and faster growing line (SD01). The effect of hybridization on carcass and meat quality (physiochemical and textural traits) was measured in the F1 population at d 91 of age. The hybrids exhibited higher body weight and dressed weight, and amount of semi-eviscerated, eviscerated, breast muscle and abdominal fat (p<0.05). Abdominal fat yield also increased (p<0.05) compared to the offspring of the two pure-lines. Meanwhile, there was no significant difference in meat quality traits except for the myofiber diameter and density and the shear force of the breast muscle. Overall, the offspring of cross-lines were similar to pure lines in meat color, pH value, inosinic acid, crude protein, crude fat, dry matter, moisture content and amino acid composition in the breast muscle. These results suggest that productivity can be improved via cross-breeding while maintaining meat quality of the Erlang mountainous chicken.

Effect of sex and dietary organic zinc on growth performance, carcass traits, tissue mineral content, and blood parameters of broiler chickens

Zinc (Zn) is an essential mineral for animal development and function. A study was carried out to evaluate the effect of sex and dietary organic zinc (OZ) on growth performance, carcass traits, tissue mineral content, and blood parameters of broiler chickens. A total of 240 1-day-old male and 240 female broiler chicks (Cobb × Cobb) were assigned to two dietary levels of OZ (2 × 2 factorial) with six replicates per treatment (20 birds/replicate pen). The OZ supplementation levels were 0 and 25 ppm. Results showed that OZ supplementation did not affect the growth performance of male and female broilers, but the males showed significantly better (P < 0.05) growth performance than females did. Similarly, OZ supplementation did not affect the thickness of both the back and thigh skin of male and female broilers; however, males had thicker skin than females. Dietary OZ supplementation did not affect collagen contents in the skin and meat samples. Male broilers had higher skin collagen contents than females, but no sex difference was found in meat collagen contents. OZ supplementation did not affect the shear force values of skin and meat samples. Male broilers had higher shear force values of back skin than females, but not in the meat samples. Dietary OZ supplementation increased (P < 0.05) the thigh meat Zn content in both sexes. The plasma Ca content was significantly (P < 0.05) increased by dietary OZ supplementation; however, other blood parameters were not affected by dietary OZ supplementation. Males had higher plasma glucose and cholesterol content than females. It is concluded that dietary OZ supplementation at the level of 25 ppm does not affect the growth performance and skin quality of broiler chickens but increases the Zn content in thigh meat and Ca content in plasma of broiler chickens. Male broilers had better growth performance and skin quality than females.

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.

Influence of rearing system on growth performance, carcass traits, and meat quality of Yangzhou geese

An experiment was conducted using a total of 540 one-day-old Yangzhou geese to study the effect of rearing system on growth performance, carcass traits, and meat quality of male and female Yangzhou geese. The birds were divided into homogeneous groups according to initial BW and sex. The male and female geese were raised in separate pens under 5 different treatments, with 3 replicate pens of 18 male or 18 female geese per pen for each treatment. This experiment included 2 stages, with geese at 1 to 28 d of age (the first stage) and 29 to 70 d of age (the second stage). The 5 different treatments were 1) system A (geese raised on a wire floor), 2) system B (geese raised on the floor), 3) system C (geese raised on the floor and transferred to to a wire floor), 4) system D (geese raised on a wire floor and transferred to the floor), and 5) system E (geese raised on the floor and transferred to a free range). Results showed that feed conversion rate, BW, and BW gain were significantly affected by rearing system and sex (P < 0.05). For carcass yield, results suggested that eviscerated carcass yield and heart yield were affected by rearing system (P < 0.05) but not by sex (P > 0.05). Differences between sexes, but not rearing systems, were observed for only breast yield, thigh yield, and liver yield (P < 0.05). Rearing system and sex had a remarkable effect (P < 0.05) on subcutaneous fat thickness, abdominal fat yield, and gizzard yield. The nutrient composition (water, protein, and fat), water-holding capacity, shear force, and pH of the pectoralis major muscle were not affected (P > 0.05) by the rearing system, and only water, protein, and pH of the meat were affected by sex (P < 0.05). This study indicates that rearing system A, in which Yangzhou geese were raised on a wire floor, improved growth performance but had little effect on meat quality, implying that the use of rearing system A, using a wire floor, might be feasible and effective for Yangzhou geese.

Relationships between single nucleotide polymorphisms of the H-FABP gene and slaughter and meat quality traits in chicken

Using PCR-SSCP with five primer pairs, we detected six single nucleotide polymorphisms of the H-FABP gene: 332G --> A, 534G --> A, 783C --> T, 835C --> T, 1198T --> C, and 2329C --> T. Chi-square results showed significant differences (P < 0.05) in genotype frequency among breeds in Fragment 1 and extremely significant differences (P < 0.01) in Fragments 2-4. We found a significant association between Fragment 2 genotype and muscle fiber number, Arg and Thr (P < 0.05); between Fragment 3 genotype and living weight, carcass weight, breast muscle weight, abdominal fat weight, and abdominal fat percentage (P < 0.05); between Fragment 4 genotype and Thr, Phe, and inosinic acid (P < 0.05). It was concluded that H-FABP was the major gene influencing slaughter performance and meat quality or was linked with the major gene in these strains and that the C783T mutation could be used as a candidate molecular genetic marker for breeding selection. The combination M1C2-B2B2-D1D1 is an ideal model for breeding in these strains because it can improve slaughter and meat quality traits.

Study on association of single nucleotide polymorphism of CAPN1 gene with muscle fibre and carcass traits in quality chicken populations

This study was aimed at investigating the effect of the calpain 1 (CAPN1) gene on carcass and meat quality traits in eight meat-type chicken populations, including five pure lines (developed from Chinese local breeds) and three cross-breeds. Primer pairs for the Coding Sequence (CDS) region in CAPN1 were designed from the chicken genomic sequence database. Polymorphisms were detected by polymerase chain reaction (PCR)-Single Strand Conformation Polymorphism (SSCP) and DNA sequencing. Three single nucleotide polymorphisms (SNP; C2546T, G3535A and C7198A) were detected among individuals in each population. The associations of their haplotypes (H1 = CGA, H2 = CGC, H3 = CAA, H4 = CAC, H5 = TGA and H7 = TAA) with chicken breast muscle fibre and carcass traits were analysed. Results showed that the haplotypes were associated with live weight (LW), carcass weight (CW), breast muscle weight (BMW) and leg muscle weight (LMW) (p < 0.05), and were also related to eviscerated percentage (%EP) and breast muscle fibre density (p < 0.01). H1H3 haplotype was dominant for LW, CW and BMW; H1H5 haplotype was dominant for EP; H3H4 haplotype was dominant for LMW and H1H1 haplotype was dominant for BFD. It was concluded that the CAPN1 gene may be a major gene affecting meat quality traits of chicken or it is linked with the major gene. H1H3, H1H5 and H3H4 were the most advantageous haplotypes for carcass traits whereas H1H1 was the positive haplotype for breast muscle fibre trait.

Effect of manganese supplementation and source on carcass traits, meat quality, and lipid oxidation in broilers1

An experiment was conducted using a total of 336 one-day-old, Arbor Acres commercial male broilers to investigate the effect of dietary Mn supplementation on carcass traits, meat quality, lipid oxidation, relative enzyme activities in abdominal fat and meat, and Mn-containing superoxide dismutase (MnSOD) mRNA level in meat. Broilers were randomly allotted by BW to 1 of 8 replicate cages (6 chicks per cage) for each of 7 treatments in a completely randomized design involving a 2 x 3 factorial + 1 arrangement of treatments. Dietary treatments included the corn-soybean meal-based diet (control) and the basal diet supplemented with 100 or 200 mg of Mn/kg as MnSO(4) x H(2)O, Mn AA A with a chelation strength of 26.3 formation quotient (8.34% Mn), or Mn AA B with a chelation strength of 45.3 formation quotient (6.48% Mn). Birds fed supplemental Mn had lower (P < 0.10) percentages of abdominal fat, lipoprotein lipase (LPL), and malate dehydrogenase activities and greater (P < 0.07) hormone-sensitive lipase activities in abdominal fat than birds fed a control diet. Birds fed supplemental Mn from Mn AA A or Mn AA B had lower (P < 0.05) LPL activities in abdominal fat than those fed supplemental MnSO(4) x H(2)O. Birds fed supplemental Mn had lower (P < 0.03) malondialdehyde content in leg muscle and greater (P < 0.02) MnSOD activities and MnSOD mRNA level in breast or leg muscle than those fed the control diet. Birds fed supplemental Mn from Mn AA A had a greater (P < 0.02) MnSOD mRNA level in leg muscle than those fed supplemental MnSO(4) x H(2)O. Results from this study indicated that organic Mn was more available than inorganic Mn for decreasing LPL activity in abdominal fat of broilers, and dietary Mn might reduce abdominal adipose deposition by decreasing LPL and malate dehydrogenase activities or increasing hormone-sensitive lipase activity in abdominal adipose tissue. The results also indicated that dietary Mn upregulated muscle MnSOD gene expression pretranslationally in association with increased MnSOD activity, which might explain the decrease of malondialdehyde content in leg muscle.

Effect of clenbuterol on athletic performance

Unlike inhaled beta 2-agonists, more studies need to be performed before the action of systemic beta 2-agonists on athletic performance can be assessed accurately. Experiments in animals with oral clenbuterol have shown augmentation in muscle bulk across numerous species, but human studies cannot confirm similar muscle mass enlargement in healthy men. Although the human studies demonstrate the potential for long-acting systemic beta 2-agonists to increase muscle strength in certain muscle fiber types, it is difficult to judge the drugs' effects on overall athletic performance, because athletic skill is more than strength, speed, and endurance. The effect of oral clenbuterol on athletic performance cannot be evaluated from its actions on muscle strength alone. However, as evidence stands now, sports regulatory agencies are correct to ban systemic beta 2-agonists until the following 2 points can be proven: (1) oral forms provide a therapeutic benefit that cannot be obtained with aerosol or inhaled forms; and (2) oral forms do not give any unfair advantage to the competitor in muscle strength, power output, or endurance. Provided they are administered as prescribed, aerosol or inhaled beta-agonists do not impart an unfair advantage or enhance athletic performance and can continue to be used in competition by athletes with EIA.