nutrition, diet, nutrients, amino acids, pigs
Glutamine is not considered an essential amino acid, however it plays an important role in the health and growth of neonates and adults. In piglets the weaning generates atrophy of the intestinal villi and growth retardation. Several studies have shown that glutamine supplementation (0.2-2%) decreases the adverse effects of post-weaning stress in piglets. The objective of this manuscript was to evaluate the effect size of glutamine supplementation on the productive performance of piglets, the consistency of their effect and the influence of other factors through the use of meta-analysis. The administration of glutamine improves the feed conversion (p <0.001), the piglets that receive glutamine convert the feed better when the supplementation lasted between 7 to 14 days (p = 0.0023), since they require 121.6 g less of feed in comparison with the control group to make 1 kg of body weight. When the supplementation is done for a period of 15 to 30 days and 7 to 30 days, the saving of feed is 70.6 g (p <0.001) and 87.3 g (p <0.001) per kg of body weight respectively. The daily weight gain is higher in 20.3 g/day (p = 0.0029) compared to the control group between 7 to 30 days of supplementation and 28.2 g/day (p = 0.0002) between 15 to 30 days. Age and weight of the piglet at the beginning of the supplementation, level of lysine, crude protein and the number of repetitions per treatment influence the effect of glutamine on the variables evaluated.