Effects of Compound Probiotics on Production Performance, Apparent Digestion Rate of Nutrients and Serum Index of Pigs at Different Stages

This experiment aimed to explore the effects of different doses of compound probiotics (a 1:1:1 mixture of Saccharomyces cerevisiae, Lactobacillus acidophilus, and Bacillus subtilis) added to the diet on pregnant sows and weaned piglets. The experiment was carried out in two stages. Experiment with pregnant sows: thirty-six second-parity Large White sows at 80 d of late gestation were randomly divided into a control group, experimental group I, and experimental group II. The control group was fed a basal diet, while experimental groups I and II were fed the basal diet supplemented with 2 g/kg and 3 g/kg of compound probiotics, respectively. The pre-experiment lasted 7 d, and the formal experiment continued until the end of lactation. The results showed that the numbers of live piglets per litter, healthy piglets per litter, litter birth weight and litter weaning weight in the experimental groups were significantly higher than those in the control group (p < 0.05). Colostrum IgG concentration in experimental group I was significantly higher than that in the control group and experimental group II (p < 0.05). Compound probiotics significantly increased colostrum immunoglobulin levels (p < 0.05). The concentrations of ammonia, carbon dioxide and PM2.5 in the barns of the experimental groups all showed a decreasing trend. Experiment with weaned piglets: a total of 160 Landrace × Yorkshire crossbred weaned piglets at 30 d of age with an initial body weight of (8.01 ± 0.13) kg were randomly assigned to four groups. The control group was fed a basal diet, while the treatment groups were supplemented with 2, 3, and 4 g/kg of compound probiotics, respectively. The results indicated that average daily gain and average daily feed intake in experimental group III were significantly higher than those in the control group, while the feed-to-gain ratio and diarrhea rate were significantly lower (p < 0.05). The apparent digestibility of crude fiber was significantly higher than that in the control group (p < 0.05), and serum IgA was significantly higher than in the other groups (p < 0.05). In conclusion, dietary supplementation with 2 g/kg compound probiotics for sows in late gestation showed the optimal effect, improving reproductive performance, colostrum immune indices and reducing harmful gases in the barn. For weaned piglets, supplementation with 4 g/kg compound probiotics improved growth performance, nutrient digestibility and serum immune indices.