Effects of distance and barriers between resources on bone and tendon strength and productive performance of broiler chickens.

Lameness or leg weakness is becoming an important problem in broilers selected for rapid growth, and although the causes are not known, sedentary behavior could be a cause. Two experiments were conducted to study the effects of distance and the presence of ramps between resources (feed and water) on bone and tendon strength, ability to stand, and productive performance. In experiment 1, straight run Ross 708 chicks (n = 1,260) were randomly assigned to 1 of 3 treatments: 1.0, 3.3, or 6.6 m between resources (6 pen replicates/treatment). In experiment 2, Cobb 500 male chicks (n = 864) were randomly assigned to 1 of 4 treatments (2 × 2 factorial, 4 pen replications/treatment) consisting of 2 distances (3 or 8 m) with (WR) or without (NR) a ramp (a triangular prism 31 cm high and 132 cm wide at the base). At d 21, 45, and 56 (experiment 1), or at d 28, 35, 42, and 49 (experiment 2), birds were weighed, killed, and tibias collected to measure breaking strength (BBS), and abdominal fat (AbF) content. At d 49 (experiment 2), calcaneus tendons were also collected to measure breaking strength (TBS). Foot pad lesions and latency to lie (LTL) were determined before killing the birds. In experiment 1, distance did not affect BBS, LTL, foot pad lesions, or BW, but at d 49, birds in the 6.6 m treatment had lower AbF than birds in the other treatments. In experiment 2 at d 49, birds in the 8 m treatment tended to have a higher BBS than birds in the 3 m treatment (P = 0.09), whereas WR birds had lower tendon breaking strength than NR birds (P < 0.01); however, LTL was highest in 8-m NR birds. Final BW was not affected by distance, but birds in the NR group were heavier than birds in the WR group. Furthermore, AbF was lower in 8 m than in 3 m birds. Our results suggest that longer distances between resources have limited effects on bone strength, but increase the LTL, and may change feeding patterns and carcass characteristics, as evidenced by the lower AbF content. Ramps or inclination affected tendon breaking strength.

Dietary supplemented and meat-added antioxidants effect on the lipid oxidative stability of refrigerated and frozen cooked chicken meat.

The oxidation of fatty acids decreases the quality and shelf-life of meats. To reduce this process, dietary supplemented and meat-added antioxidants were evaluated on the lipid oxidative stability of cooked chicken meat. Broilers were fed 2 levels of vitamin E (10 or 100 mg•kg(-1) of feed; VE-10 and VE-100, respectively) or oregano essential oil (100 mg•kg(-1) of feed; OR-100). Additionally, honey (3%) or butylated hydroxytoluene (0.02%; BHT) were added to chicken meat from the control treatment (VE-10). Breast meat was ground, formed into patties, and cooked on electric grills until it reached an internal temperature of 74°C. Cooked meat was cooled at room temperature, packaged, and stored under refrigeration for 9 d (4°C) or frozen for 45 d (-20°C). The 2-thiobarbituric acid reactive substance test was used to quantify malondialdehyde (MDA) values in the meat. Data were analyzed using a repeated measures design, 5 treatments with 12 replications each, and the least squares means were compared with 4 orthogonal contrasts. The results showed that the meat of the VE-10 treatment had higher values of MDA (P ≤ 0.05) compared with the other antioxidant treatments in all the storage days. There were no differences (P ≥ 0.05) in MDA values between the dietary supplemented and meat-added antioxidant treatments. The meat added with honey had lower MDA values than the one with BHT (P ≤ 0.05). Meat of the VE-100 treatment showed lower MDA values than the one of OR-100 (P ≤ 0.05) in most storage days. In conclusion, supplementation of 10 mg•kg(-1) of vitamin E to the diet resulted in a higher development of lipid oxidation in the meat. Both dietary supplemented or meat-added antioxidants had similar effects on the lipid oxidative stability. The addition of honey maintained longer the lipid oxidative stability of the meat than BHT. Finally, dietary supplementation of vitamin E at the same level of oregano oil, 100 mg•kg(-1), resulted in a higher antioxidant effect on the meat.