Response surface methodology (RSM) was used to optimize the cultivation conditions for the production of phytase by recombinant Escherichia coli DH5α. The optimum predicted cultivation conditions for phytase production were at 3 hours seed age, a 2.5% inoculum level, an L-arabinose concentration of 0.20%, a cell concentration of 0.3 (as measured at 600 nm) and 17 hours post-induction time with a predicted phytase activity of 4194.45 U/mL. The model was validated and the results showed no significant difference between the experimental and the predicted phytase activity (P = 0.305). Under optimum cultivation conditions, the phytase activity of the recombinant E. coli DH5α was 364 times higher compared to the phytase activity of the wild-type producer, Enterobacter sakazakii ASUIA279. Hence, optimization of the cultivation conditions using RSM positively increased phytase production from recombinant E. coli DH5α.
An experiment was carried out to estimate the meat quality characteristics of village chickens (Gallus gallus) fed diets supplemented with dry leaves of Borreria latifolia (BL) used as a potential antioxidant source in chicken feed. In this study, 252 sexed 9-week-old village chickens with mean live body weight of 1,525.4 g for males and 1,254.1 g for females were divided into 7 groups (each group 18 birds) for each sex represented in 2 experiments. The first experiment was to evaluate the antioxidant activity of BL and the effect on meat quality through a comparison with Rosmarinus officinalis (RO); hence, 3 groups were conducted and included: T1 (control), basal diet without supplementation; T2, basal diet with 1% of BL; T3, basal diet with 1% of RO. T2 and T3 significantly affect pH value, lipid oxidation, cooking loss, and overall acceptability compared to T1, while no significant difference was observed between the dietary groups in respect of drip loss, color, tenderness, fatty acid profile, and meat composition. Furthermore, a significant effect of sex on lipid oxidation, pH, yellowness, and fatty acid profile was observed. There was no significant effect of sex on WHC, tenderness, lightness, redness, and sensory evaluation. A significant influence of postmortem aging period was detected on lipid oxidation, pH, tenderness, cooking loss, and redness. The obtained result in this study revealed a significance in the interaction of herb by sex in pH parameter and between herb and sex, herb by aging period, sex by aging period, and the herb by sex by aging period interactions with regard to lipid oxidation test. The second experiment was to estimate the effect of 3 different levels of BL on meat quality. Four groups were provided and involved: T1 (control), basal diet without supplementation; T2, basal diet with 1.5% of BL; T3, basal diet with 2% of BL; and T4, basal diet with 2.5% of BL. The result of this study showed a significant effect (P < 0.05) of the dietary groups on redness value, sensory evaluation, and lipid oxidation. A significant effect of sex on fatty acid profile and lipid oxidation was detected in addition a significant effect of postmortem aging period on redness, pH, tenderness, cooking loss, and lipid oxidation was noticed. There was no significance in the interaction between herb and sex through pH test while a significance in the interaction between herb and sex, herb × aging period, sex × aging period, and herb × sex × aging period interactions with regard to lipid oxidation was found. It can be concluded that dietary supplementation of BL improved oxidative stability and enhanced meat quality.
This study evaluated the effect of partial uropygialectomy (PU) on carcass traits of male and female Akar Putra chickens. Sixty chicks of each sex were evenly distributed into 5 treatment groups with 3 replicates per group containing 4 males and 4 females each, and reared for 12 wk. Homogeneity of the groups was satisfied with regard to the parity. Experimental treatments consisted of a control treatment (T1), and partial ablation of the uropygial gland was applied on the second, third, fourth, and fifth treatments at 3, 4, 5, and 6 wk of age, respectively. The chickens were fed ad libitum the same diets (1 to 13 d: starter; 14 d to slaughter: finisher). On the last d of the experiment, 12 birds were randomly selected from each treatment group (2 males and 2 females per replicate) and slaughtered to determine carcass characteristics, which included carcass weight, dressing percentage with or without eating giblets, and the relative weights of heart, liver, gizzard, thighs, wings, breast, back, and neck. From the results of the study, it was shown that the partial ablation of the uropygial gland at all ages had certain dependent effects concerning some carcass parameters, as shown by higher breast and back relative weights in males and breast relative weight in females. As a consequence, a positive effect also was noticed regarding the carcass morphology in terms of the increase in dressing percentage with or without eating giblets thus leading to an increase in the body weight and carcass weight. Furthermore, the best result was obtained in the second treatment when PU was applied at 3 wk of age compared with other experimental groups. Moreover, the current study provides a novel and economic alternative to enhance the body performance of poultry in general and Akar Putra chicken particularly.
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