A 42-d experiment was conducted with 276 Arbor Acres broilers (1 d of age, weighing 41.1 ± 1.5 g) to determine the effects of Forsythia suspensa extract (FSE) and berberine (BE) on growth performance, immunity, antioxidant activities, and intestinal microbiota stocked at high stocking density (28 kg of BW/m(2) as the normal density, 46 kg of BW/m(2) as the high density). The feeding program consisted of a starter diet from d 1 to 21 of age and a finisher diet from d 22 to 42. Dietary treatments included (1) negative control group (NC), stocked at high density; (2) positive control group (PC), stocked at normal density; (3) FSE, NC + 100 mg/kg of FSE; (4) BE, NC + 100 mg/kg of BE; and (5) FSE + BE, NC + 100 mg/kg of FSE + 100 mg/kg of BE. Birds had free access to diets and water. Body weight and feed intake were measured at d 21 and 42. Blood, spleen and bursa, and intestinal contents were collected at d 42 for analysis. The results showed that growth performance did not differ among treatments in the starter period; however, in the finisher and overall periods, birds in FSE + BE, FSE, BE, and PC had greater final BW, ADG, and ADFI than the birds in NC (P < 0.05). The birds in FSE + BE, FSE, BE, and PC had greater bursa weight, bursa weight/BW ratio, serum total antioxidant capacity, and superoxide dismutase activity than birds in NC (P < 0.05). The FSE + BE, FSE, and BE birds had lower serum malondialdehyde level than NC birds (P < 0.05). The FSE + BE, FSE, BE, and PC birds had lower counts of Escherichia coli but greater Lactobacillus in the cecum than that of NC birds (P < 0.05). Dietary supplementation with FSE, BE, or both can improve the growth performance possibly by enhancing immunity, reducing oxidative stress, and promoting intestinal colonization by healthy microbiota of broilers under high stocking density.

Two experiments were conducted to evaluate the efficacy of feeding an Escherichia coli (E. coli) derived phytase to pigs fed P deficient, corn-soybean meal diets. In Exp. 1, one hundred and twenty crossbred piglets (9.53±0.84 kg) were allocated to one of five treatments which consisted of four low P diets (0.61% Ca, 0.46% total P and 0.24% non-phytate P) supplemented with 0, 500, 1,000, or 20,000 FTU/kg E. coli phytase as well as a positive control formulated to be adequate in all nutrients (0.77% Ca, 0.62% total P and 0.42% non-phytate P). The treatments were applied to six pens with four pigs per pen for 28 days. In Exp. 2, ten crossbred pigs (19.66±1.16 kg) fitted with ileal T-cannula were used in a nutrient balance study. The pigs were assigned to treatments similar to those used in Exp. 1 in a doubly replicated 5×4 incomplete Latin square design (5 diets with 4 periods). Each period consisted of a 5-d adjustment period followed by a 3-d total collection of feces and urine and then a 2-d collection of ileal digesta. Supplementation with phytase linearly increased (p<0.05) weight gain, feed intake, feed efficiency, bone breaking strength and fat-free dry and ash bone weight. There were linear increases (p<0.01) in the apparent ileal digestibility (AID) of DM, GE, CP, Ca, total P, inositol hexaphosphate (IP6) and some AA with increasing dose of E. coli phytase. Pigs fed 20,000 FTU/kg had a greater (p<0.05) AID of IP6 (80% vs 59% or 64%, respectively) than pigs fed diets with 500 or 1,000 FTU/kg phytase. There were linear increases (p<0.05) in the total tract digestibility of Ca, total P, Na, K, Mg, and Zn as well as in the retention of Mg and Zn with increased phytase dose. The retention and utilization of Cu, and the total tract digestibility of CP and Cu quadratic increased (p<0.05) with increased phytase dose. In conclusion, supplementation of 500 FTU of phytase/kg and above effectively hydrolyzed phytate in low-P corn-soybean diets for pigs. In addition, a super dose of phytase (20,000 FTU/kg) hydrolyzed most of the IP6 and consequently further improved mineral use, protein utilization and performance.

Three experiments were conducted to evaluate the metabolizable energy (ME) value, standardized ileal digestibility (SID) of amino acids (AA) of soybean meal (SBM), soy protein concentrate (SPC) and fermented soybean meal (FSBM), and the application of these products in early-weaned piglets. In Exp. 1, four barrows with initial body weight (BW) of 14.2±1.4 kg were used in a 4×4 Latin square design. The diet 1 contained corn as the only energy source. The other three diets replaced 25% of corn in diet 1 with one of the three soybean products, and the digestable energy (DE) and ME contents were determined by difference. In Exp. 2, four barrows (initial BW of 18.2±1.5 kg) were fitted with ileal T-cannulas and allotted to a 4×4 Latin square design. Three cornstarch-based diets were formulated using each of the soybean products as the sole source of AA. A nitrogen-free diet was also formulated to measure endogenous losses of AA. In Exp. 3, ninety six piglets (initial BW of 5.6±0.9 kg) weaned at 21±2 d were blocked by weight and assigned to one of three treatments for a 21-d growth performance study. The control diet was based on corn and SBM, the two treatments’ diets contained either 10% SPC or FSBM and were formulated to same SID lysine to ME ratio of 3.6 g/Mcal. The results showed that the ME content of SPC was greater than SBM (p<0.05). The SID of most AA in SPC was greater than the SID of AA in SBM (p<0.05). For the essential AA, the SID of histidine, isoleucine, leucine, lysine and threonine in FSBM were greater than in SBM (p<0.05). Even though they were fed same SID lysine to ME ratio of 3.6 g/Mcal diets, pigs fed SPC and FSBM diets had greater weight gain, G:F (p<0.05) and better fecal score (p<0.05) than pigs fed SBM diet. In conclusion, SPC showed a higher ME content and SID of AA than the SBM. SID of some essential AA in FSBM was higher than SBM and was similar with SPC. But the lower antigenic proteins and anti-nutritional factors content in SPC and FSBM may be the main factors affecting the performance of early-weaned piglets rather than the increased ME content and SID of AA.