The ban of antibiotic growth promoters in many countries necessitate the need for alternatives. This study aimed to assess the growth-promoting potency of nano-phytobiotics (NP) on broiler chickens by using a meta-analysis approach. A systematic search was conducted using online databases. Data of average daily feed intake (ADFI), average daily gain (ADG), and feed conversion ratio (FCR) were pooled using a random-effect model and the overall effect size was quantified using mean difference (MD). Heterogeneity among the studies was checked using I2 statistics. A total of 11 studies (31 comparisons) using 3,584 broiler chickens were involved in this meta-analysis. Inclusion of NP had no significant effect on ADFI (MD=-1.20 g/bird/d; P=0.157; I2=32%). However, NP significantly improved ADG (MD=2.16 g/bird/d; P=0.002; I2=90%) and FCR (MD=-0.09; P<0.001; I2=91%). Subgroup analysis revealed that NP significantly improved (P<0.05) ADG when the studies using dose of 45-200 and 1,000-10,000 ppm, as well as 42 d study period. Meta-regression analysis also indicated that ADG improvement significantly associated (P<0.05) with the NP dose and study duration, which could explain 21% and 20% of heterogeneity, respectively. This meta-analysis provides evidence that NP inclusion could improve ADG and FCR without alter ADFI on broiler chickens. However, their efficacy may vary according to the NP dose and study duration.

The rearing of calves is a difficult period for farmers due to health problems to which the animals are prone this time. Since the use of antibiotics as growth promoters has been forbidden, various innovative feed additives have been tested in many countries around the world. In this study, experimental (E) calves were supplemented with a novel feed additive consisting of the pancreatic-like enzymes protease and lipase, a fat-coated mixture of organic fumaric, malic, citric and sorbic acids, sodium butyrate and silicon dioxide nanoparticles. Control (C) calves received feed without additive. During the supplementation, white blood cell (WBC) counts with leukocyte differentiation, percentages of B lymphocytes and T lymphocytes and their subpopulations, phagocytic activity and oxidative burst of circulating monocytes and granulocytes were examined. Body weight (b.w.) gains of the calves were also monitored. The WBC counts in the E and C calves were within the reference ranges throughout the study. In the analysis of the percentages of the lymphocyte subpopulations, phagocytic activity and oxidative burst, no statistically significant differences were reported between the E and C groups. However, higher average daily body weight gains were obtained for the E calves. The study revealed that the examined feed additive did not modulate the immune response of the calves significantly. The tendency to higher daily average b.w. gains in the E calves than in the C calves suggests a beneficial effect of this feed additive.