The present study was conducted to evaluate four commercially available phytase sources supplemented at regular (R) and super-dose (S) levels on live performance, bone mineralization, and apparent ileal digestible energy. Broiler chickens were allocated in stainless steel battery brooders (six birds per cage and eight pen replicates per treatment). A basal diet formulated to contain 0.2% non-phytate phosphorus (NPP) and 0.7% Ca was subdivided to create 11 dietary treatments: (1) basal diet was kept as the negative control (NC); (2) NC + limestone and monoclacium phosphate to create positive controls 1 and 2 formulated to yield 0.3% and 0.4% NPP; (3) NC + phytase A (250 and 1,500 FTU/kg); (4) NC + phytase B (500 and 1,500 FTU/kg); (5) NC + phytase C (500 and 1,000 FTU/kg); (6) NC + phytase D (1,000 and 2,000 FYT/kg). Performance was evaluated on d 7, 14, and 22. Tibia bone ash, tibia breaking strength, bone mineral content, and bone mineral density were evaluated on d 22. Apparent energy digestibility was evaluated on d 24. At d 7, phytases A and C supplemented at S level improved (P < 0.05) body weight and weight gain when compared to the NC. At d 14 and 22, all phytase sources improved (P < 0.05) body weight, weight gain, and bone mineralization when compared to the chicks under the NC diet. Overall, phytase supplementation at S level improved 17% apparent ileal digestibility at 24 d. Throughout the grow out period, phytase super-dose yield (P < 0.05) better performance, bone characteristics, and energy digestibility than the regular dietary level. In conclusion, all phytase sources were able to compensate the phosphorus deficiency and promote performance and bone mineralization. High levels of phytase showed a higher response when compared to the lower levels of supplementation.

This study evaluated egg production and quality variables of caged and free-range Hy-Line Brown laying hens fed soybean meal (SBM) and soybean-meal-free (SBMF) diets. Hens were randomly assigned to the same 2 dietary treatments within 3 location blocks. SBM and SBMF diets with equivalent calculated nutrient content were prepared based on Hy-Line Brown rearing guidelines. The SBMF diets utilized cottonseed meal, corn distillers dried grains with solubles, corn gluten meal, and wheat middlings in place of dehulled soybean meal. The experiment was conducted between August 2015 and January of 2016 within the TAMU Poultry Research Center and data analyzed over 6 consecutive 28-day periods. Data were analyzed as a split-plot with rearing systems designated whole plots and diets designated as subplots. Hens reared in the free-range rearing system peaked a couple of wk later than those hens within the more conventional indoor caged system, and cumulative production data were considerably more variable for hens raised in the free-range environment. Cumulative egg production, feed per dozen eggs and feed conversion ratio (g feed/g egg) were 92 ± 1.23 and 86 ± 1.84%, 1.45 ± 0.02 and 1.89 ± 0.05 kg, and 2.14 ± 0.04 and 2.77 ± 0.08 (P < 0.05), respectively, for the caged vs. free-range rearing systems. Cumulative egg weight, feed per dozen eggs, and feed conversion ratio were 59.9 ± 0.59 and 56.5 ± 0.60 g, 1.57 ± 0.04 and 1.77 ± 0.05 kg, and 2.24 ± 0.06 and 2.67 ± 0.08 kg (P < 0.05) for SBM and SBMF diets, respectively. Diet did not affect cumulative egg production (P > 0.05). With respect to egg quality, there were no differences in cumulative albumen height, Haugh unit, or breaking strength, but there was a significant rearing system by diet interaction for shell thickness, with the free-range hens averaging 40.77 ± 0.19 and 39.86 ± 0.31 μm (P < 0.05), respectively, for the hens fed SBM vs. SBMF diets. In conclusion, the results suggested free-range production is more variable than traditional closed-house cage systems based on standard errors, and SBMF diets containing cottonseed meal can be used in both caged and free-range production systems without affecting egg production, although one might see lower egg weights.

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White striping ( WS ) and woody breast ( WB ) have been previously associated with older and heavier birds. However, there is limited information supporting the association between these 2 muscle conditions and growth parameters. The objectives of this study were 1) to investigate the relationship between WS and WB using different growth production factors and 2) to propose a predictive model that uses growth production factors to investigate the incidence and severity of WS and WB. A combined database of 4,332 broilers pooled from 7 research experiments conducted from 2016 to 2017 at Texas A&M University was used in this study. Parameters such as sex, age (4 wk, 6 wk, and 8 wk), strain (standard A vs. high-breast-yield [B and C]), live weight categories (500 g increments), and breast weight categories (250 g increments) were included in the model. Results showed that WS was 12% more likely to be present in non-WB fillets. The association between WS and WB suggests a moderate relationship between the ranks of both outcome variables (ρ = 0.57, P < 0.0001). Variables such as age, live weight, and sex were not as important as breast weight and strain in the severity prediction of WS and WB. Butterfly fillets above 750 g and with high-breast-yielding strains were more likely associated with higher severity of WS and WB scores. No post hoc variable selection was performed. Both models show good discrimination. The WS model produced an uncorrected area under the curve ( AUC ) of 0.739, with a bootstrap corrected estimate of 0.736. The WB model produced an uncorrected AUC of 0.753 and a bootstrap corrected estimate of 0.752. Therefore, the growth production factors analyzed in this study indicated that there is a moderate relationship between WS and WB myopathies and were jointly predictive of the severity of WS and WB. Potentially other factors not included in this study may play a major role in the relationship of these 2 myopathies. More research should be done to investigate this possibility.

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