A total of 180 twenty-eight-day-old weaning pigs [Duroc  (Yorkshire  Landrace)] with an average body weight of 7.62 ± 1.25 kg were used in a 42-day trial to evaluate the effect of probiotics mixture supplementation on weaning pigs. Pigs were randomly allotted to one of four dietary treatments: (1) CON, basal diet, (2) T1, CON þ 0.1% probiotics mixture, (3) T2, CON þ 0.2% probiotics mixture, and (4) T4, CON þ 0.3% probiotics mixture. Increasing dietary inclusion of probiotics mixture levels linearly increased average daily gain (ADG) and average daily feed intake (ADFI) during day 0-7 as well as ADG and gain to feed ratio (G:F) during day 8-21 (p < .05). There was a quadratic effect in improving ADFI during day 0-7, day 22-42, and ADG during day 8-21 (p < .05). In addition, increasing inclusion of probiotics mixture levels in the diets linearly increased (p < .05) dry matter (DM), nitrogen (N), energy digestibility, and faecal Lactobacillus counts and decreased Escherichia coli counts and ammonia (NH 3) emission. However, no significant differences were observed in ADG, ADFI, G:F during day 22-42, and day 0-42 except for a quadratic increase of ADFI for day 22-42 (p < .05). Feeding the pigs with the diets containing different probiotics mixture levels did not affect the faecal hydrogen sulfide emission (p>.05). In conclusion, increasing inclusion of probiotics mixture up to 0.3% linearly improved growth performance during day 0-7 and day 8-21. Pigs fed the diets with probiotics mixture suplementation improved the nutrient digestibility, faecal bacterial enumeration, and decreased NH 3 emission. HIGHLIGHTS Probiotics mixture supplementation increased growth performance and nutrient digestibility in weaning pigs. Increased fecal Lactobacillus and reduced E. coli counts. Reduced fecal ammonia emission that can contribute in reducing environmental pollution.

We investigated the effects of a blend of organic acids (OAs) and medium-chain fatty acids (MCFAs) supplementation in 800 1-d-old male Ross 308 broiler chickens (42 ± 0.90 g) in a 7-week study. Broiler chicks were randomly allocated into one of the five dietary treatments (16 birds per pen with 10 pens per treatment). Dietary treatments consisted of corn-soybean meal based basal diet and the basal diet supplemented with blend of OAs and MCFAs at 0.25, 0.5, 0.75 g, and 1 g per kg of feed. In the current study, during the whole experimental period, the inclusion of the blend of OAs and MCFAs in the basal diet linearly improved (p < 0.05) body weight gain (BWG), feed conversion ratio (FCR), and dry matter digestibility. The increasing inclusion of the blend of OA and MCFA levels in the diets linearly decreased (p = 0.002) feed intake during d 1 to 7. Broilers fed diets containing different levels of the blend of OAs and MCFAs showed a linear increase (p = 0.006) in Lactobacillus concentrations and decrease (p = 0.014) in ammonia (NH3) at the end of the experiment. However, the blend of OAs and MCFAs did not affect carcass quality, E. coli, and Salmonella counts, as well as hydrogen sulfide and total mercaptans gas emission (p > 0.05). In conclusion, the blend of OA and MCFA supplementation positively influenced growth performance, DM digestibility, excreta Lactobacillus counts, as well as NH3 gas emission in broiler chickens.

Due to the increasing safety concerns about the risk of spreading antibiotic resistance in the environment, and the presence of chemical residues in animal products, using organic acids (OAs) to replace antibiotic in the diet of farm animals has increased considerably in recent years. It has been suggested that OAs could attribute to diverse elements such as antimicrobial activity, decreasing the pH of digesta particularly in the gastrointestinal tract (GIT), slowing feed transit in the GIT to maximize feed digestion and nutrient absorption, inducing enzyme secretion and activity in the small intestine, and providing nutrients to intestinal tissue. It has been reported that OAs mixture might be more effective than individual OAs due to the synergistic effects of different pKa values and have a broad-spectrum activity. In conclusion, this review showed that an OA mixture, which can improve nutrient digestibility and growth performance, modulate intestinal bacterial populations and improve gut health, as well as decreasing gas emission, can be used as alternative to antibiotic growth promoters. However, the results of OA mixtures are not always consistent, and the response to dietary OAs could be affected by the type of OAs, dosage, feed formula, and the age of animals. In this review, we will give an overview of the current use of OAs mixture in swine feed.

A total of 180 crossbred pigs [(Landrace × Yorkshire) × Duroc] with an average body weight of 22.61 ± 1.23 kg were used in an 18 wk study to determine the effect of protease and bromelain in low-protein diets in grower–finisher pigs. Dietary treatments included: T1, basal diet treatment; T2, low-protein treatment; T3 (T2 + 0.2 g kg−1 protease); and T4 (T2 + 0.3 g kg−1 bromelain). Pigs fed protease- and bromelain-supplemented diets increased average daily gain and gain to feed ratio at week 18, dry matter and nitrogen digestibility at week 6, as well as energy digestibility at week 12, compared with low-protein diet (P < 0.05). Pigs fed T3 and T4 diets led to a trend of decreased (P < 0.05) blood urine nitrogen (BUN) and creatinine concentrations at the 12th wk. A reduction of ammonia (NH3) and hydrogen sulfide (H2S) emission was observed in pigs fed the dietary protease and bromelain supplementation at the 6th wk (P < 0.05). There was no effect on all parameters between the protease and bromelain supplementation treatments. In conclusion, supplementation of protease and bromelain to low-protein diet enhanced growth performance, nutrient digestibility, and reduced NH3 and H2S in growing–finishing pigs.

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