Phase feeding in a big-bird production scenario: Effect on growth performance, yield, and fillet dimension

Meat quality attributes of male and female broilers from 4 commercial strains processed for 2 market programs

In recent times, meat quality has become a key aspect of poultry production. In the current study, 2,400 sex separate broilers from 4 commercial strains were placed in 6 replications to evaluate various meat quality characteristics when grown to 2 market weights. Broilers were fed 1 of 2 diets with varying degrees of amino acid inclusion to evaluate meat quality of broiler raised on varying planes of nutrition. Birds were processed to meet 2 specified target weights (2.5 and 3.8 kg) representing small bird and big bird debone markets in the United States, respectively. Birds were processed using commercial methods, deboned at 3-h postmortem, and meat quality was assessed. Myopathies (woody breast, white striping, spaghetti meat, along with tenderloin quality), fillet dimensions, color, water-holding capacity (e.g., drip loss, cook loss), and Meullenet Owens Razor Shear was determined. Data were analyzed using the Mixed Model platform of JMP Pro 15.2 (SAS Institute, Cary, NC). Diet had no effect (P > 0.05) on the key quality responses; data were then pooled resulting in main effects of sex, strain, and target weight (noted as carcass size). On the day of processing, high yielding (HY) strains produced higher breast and tender yields (P < 0.05) when compared to standard yielding (SY) strains. In addition, and as expected, females exhibited higher breast and tender yields (P < 0.05) than males. However, males had significantly thicker (P < 0.05) and longer (P < 0.05) fillets, higher incidences (P < 0.05) of white striping, and higher (P < 0.05) cook loss when compared to females. Differences were also observed in tenderness as SY strain A produced the lowest shear values, whereas SY strain B produced the highest shear values across parameters (P < 0.05). SY strains in the small bird (SB) market performed better than SY strains in the big bird (BB) market as indicated by lower incidences of breast and tender myopathies white striping, woody breast, spaghetti meat, woody-like tender, and tender feathering and improved quality attributes (P < 0.05). Similar trends were observed (P < 0.05) in HY strains as SB carcasses produced a better overall product than BB. Differences in carcass size directly impacted quality (P < 0.05) as SB markets showed improvements in most parameters assessed, but broilers representing BB markets had greater breast yield. Although strain had minimal impacts on quality measures, carcass size, and sex had a greater impact on muscle myopathies, water-holding capacity, and shear properties.

Characterization of growth patterns and carcass characteristics of male and female broilers from four commercial strains fed high or low density diets

Over the last few decades, the poultry industry has seen the emergence of various market segments that are beneficial for rearing various flock sizes. Two concurrent experiments consisting of 1,200 broilers each were conducted to evaluate the effects of broiler size and diet on the performance of four commercially available broiler strains, including 2 standard yielding (SY) and 2 high yielding (HY) strains. Within each experiment (Experiment 1: males, Experiment 2: females), a small bird (38 and 40 d processing) and big bird (47 and 54 d processing) debone market were targeted to give variable carcass size. Two polyphasic diets were fed based on varying of amino acid densities. The low-density diet (L) consisted of 1.20, 1.10, 1.00, and 0.96% digestible Lys and the high-density diet (H) consisted of 1.32, 1.21, 1.10, and 1.06% across the 4-phases, respectively, with similar essential amino acid to digestible Lys ratios between the L and H diets in each phase. Weekly BW, BW gain, feed intake, and feed conversion ratio were assessed, as well as processing yields during both experiments. Broilers fed the H diets responded better than those fed the L diets, regardless of sex, with increased BW and decreased FCR (P < 0.05). Male HY strains provided the highest carcass yields (P < 0.05) compared to SY strains, with no differences observed in females (P > 0.05). High density diets (Diet H) also produced increases in carcass, breast, and tender yield (P < 0.05) for males, but that trend was not present in carcass yield for females (P < 0.05). Overall, strain impacted performance traits and carcass yields. Therefore, the use of specific strains and amino acid density for various market segments is beneficial for integrators to maximize return.

Effects of dynamic segmentation of nutrient supply on growth performance and intestinal development of broilers

This experiment was to investigate the effects of dynamic segmentation of interval nutrient supply phase feeding on the growth performance, carcass characteristics, immune organs indexes and intestinal morphology of broilers. A total of 320 one-day-old broilers were randomly assigned into 4 feeding treatments, which included 4 interval nutrient supply phases as follows. Treatment A: a nutrient supply standard was used for every 14 d. Treatment B: a nutrient supply standard was used for every 7 d. Treatment C: a nutrient supply standard was used for every 3.5 d except that one nutrient supply standard was used for d 1 to 7. Treatment D: a nutrient supply standard was used for every 3.5 d including d 1 to 7. Each treatment was represented by 8 replicates with 10 broilers per replicate. The trial lasted for 42 days. Throughout the 42 d trial period, treatment A showed significantly higher average daily gain than treatments B and C (P < 0.05). The feed:gain ratio of treatment A was significantly lower than those of treatments C and D (P < 0.05). On d 28 and 42, body weight of broilers in treatment A was much higher than those of treatments B and C (P < 0.05). The slaughter rate of treatment A was significantly higher than that of treatment B (P < 0.05). Eviscerated percentage of treatment A was significantly higher than those of treatment B and D (P < 0.05). There were no significant differences among 4 treatments in immune organs indexes (P > 0.05). The crypt depth of duodenum was significantly greater in treatments A and B than in treatment C on day 42 (P < 0.05). Meanwhile, the ratio of villus height to crypt depth (V:C ratio) of treatment D was significantly higher than that of treatment A (P < 0.05). No significant differences were found between treatments C and D in growth performance, carcass performance, immune organs indexes and intestinal structure (P > 0.05). In conclusion, this study revealed that the growth and carcass performance of broilers is the best for 14 days segmentation phase feeding, and 3.5 days segmentation interval phase feeding can promote small intestinal development of broilers. Dynamic segmentation of dietary supply fails to affect the immune function of broilers.

Dietary lysine affects chickens from local Chinese pure lines and their reciprocal crosses

The objective of this experiment was to evaluate the effect of dietary lysine concentration on meat quality and carcass traits in 2 chicken lines, SD02 and SD03, and their crosses, both originating from a Chinese native breed, the Erlang Mountainous chicken. The lines were selected for 4 generations by Sichuan Agricultural University (Ya'an, China); for the present study, chickens from the 2 lines and their crosses were randomly assigned at hatch to 1 of 2 dietary groups. One group was offered diets containing 1, 0.85, and 0.70% total lysine, whereas the other was offered diets with 1.15, 1, and 0.85% total lysine from d 1 to 28, d 29 to 49, and d 50 to 70, respectively. In total, 252 chickens were commercially processed at 70 d old. Traits measured included live BW, subcutaneous fat thickness, weight of carcass, eviscerated carcass, semi-eviscerated carcass, breast muscle (left pectoralis major and minor), leg muscle (boneless left drum plus thigh), heart, gizzard, proventriculus, spleen, liver, comb, and abdominal fat, color parameters lightness, redness, or yellowness (L*, a*, and b*), pH, and breast muscle intramuscular fat content. The results indicated that, although dietary lysine concentration did not affect subcutaneous fat thickness, color parameters, pH, intramuscular fat content, and organ weights, there were effects on feed conversion and muscle and BW (P < 0.05). Males and females displayed major differences in feed conversion, BW, muscle growth, and organ weight. The Line SD02 chickens grew faster and displayed less fat deposition and superior feed conversion compared with Line SD03 and the reciprocal crosses. In conclusion, performance of the chicken stocks evaluated in this study differs substantially in muscle weight and carcass weight.