Prediction of calcium and phosphorus requirements for pigs in different bodyweight ranges using a meta-analysis.

Several studies have focused on Ca and P requirements for pigs. These requirements are estimated from their retention and bone formation. However, modern pig breeds have different responses to dietary Ca and P than traditional breeds, and their requirements are expected to change on an annual basis. Besides individual Ca and P needs, the Ca to P ratio (Ca/P) is an important factor in determining requirements. This study aimed to implement a linear and quadratic regression analysis to estimate Ca and P requirements based on average daily gain (ADG), apparent total tract digestibility (ATTD) of Ca (ATTD-Ca), ATTD of P (ATTD-P), and crude protein (CP) digestibility. Results show that Ca/P had linear and quadratic effects on ADG in the phytase-supplemented (PS) group in both the 6-11 kg and 11-25 kg categories. In the latter category, the CP digestibility was linearly increased in response to increasing Ca/P in the without-phytase (WP) group. In the 25-50 kg category, there was a linear response of ADG and linear and quadratic responses of CP digestibility to Ca/P in the PS group, while a linear and quadratic increase in CP digestibility and a quadratic effect on ATTD-Ca were observed in the WP group. In the 50-75 kg category, Ca/P had significant quadratic effects on ADG in the PS and WP groups, along with significant linear and quadratic effects on ATTD-Ca. In addition, Ca/P had significant quadratic effects on ATTD-P and led to a significant linear and quadratic increase in the CP digestibility in the WP group. In the 75-100 kg category, analysis showed a significant decrease in ATTD-Ca and ATTD-P in the PS and WP groups; in the latter, ATTD-P and ATTD-Ca were linearly decreased by increasing Ca/P. In conclusion, our equations predicted a higher Ca/P in the 6-25 kg bodyweight categories and a lower Ca/P in the 50-100 kg category than that recommended in the literature.

Muscle Antioxidant Activity and Meat Quality Are Altered by Supplementation of Astaxanthin in Broilers Exposed to High Temperature.

This study investigated the effect of dietary astaxanthin (AST) on the meat quality, antioxidant status, and immune response of chickens exposed to heat stress. Four hundred and eighty male broilers were assigned to four treatments including AST0, AST20, AST40, and AST80 with 0, 20, 40, and 80 ppm astaxanthin supplementation levels, respectively. There was a linear decrease of malondialdehyde (MDA) in leg muscle. Catalase and superoxide dismutase levels in the plasma were linearly increased. There was a linear increase in the level of total antioxidant capacity in the leg muscle. The 3-ethylbenzothiazoline-6-sulfonate reducing activity of leg muscle was significantly increased in the AST80 treatment. The AST40 treatment showed an increase in 2,2-diphenyl-1-picrylhydrazyl radical scavenging capacity of leg muscles. Breast meat redness and yellowness were linearly increased. The astaxanthin-supplemented treatments exhibited lower drip loss and MDA concentration of leg muscle compared with the AST0 treatment at days 3 and 9 of storage. Supplementation of 40 or 80 mg/kg astaxanthin significantly decreased heat shock protein (HSP)27, HSP70, tumor necrosis factor alpha, and interleukin-6 expression in the livers. The feather corticosterone was significantly lower in the astaxanthin-supplemented treatments than in the AST0 treatment. In conclusion, astaxanthin decreased the hyperthermic stress level and improved meat quality, and antioxidant status of chickens exposed to heat stress.

Comparative standardized ileal amino acid digestibility and metabolizable energy contents of main feed ingredients for growing pigs when adding dietary ß-mannanase.

The present study was conducted to test whether the dietary supplementation of ß-mannanase affects amino acids (AA) digestibility, metabolizable energy (ME) contents of corn, wheat, soybean meal, distillers dried grains with solubles, and palm kernel meal (PKM), nutrient digestibility, and growth performance of pigs. In Exp. 1, 22 cannulated pigs were used for 10 dietary treatments including 5 feed ingredients and 2 ß-mannanase concentrations (0 and 0.5 g/kg of the diet) in 6 periods in an incomplete Latin square design to determine the AA and energy digestibility. In Exp. 2, 200 growing pigs were randomly allotted to 4 treatments with 2 nutrient levels (high and low) and 2 concentrations of ß-mannanase (2 × 2 factorial arrangement) in 2 phases (phase 1, d 0 to 21; and phase 2, d 22 to 42). In Exp. 1, ß-mannanase increased the mean standardized ileal digestibility (SID) of AA in all feed ingredients. The amount of digestible energy was increased (P < 0.05) in ß-mannanase-treated PKM. Pigs fed ß-mannanase showed a greater (P < 0.05) digestibility of gross energy (GE). The feed-to-gain (F:G) ratio was improved (P < 0.01) in pigs fed high-nutrient diets. Pigs fed ß-mannanase in the diets had greater (P < 0.05) average daily gain and F:G. In phase 2, the concentration of fecal ammonia was decreased (P < 0.05) in pigs fed ß-mannanase. Considering the 2 experiments, it can be concluded that ß-mannanase increases the SID of AA, which has to be considered in balancing the rations.