Suplementação in ovo de vitaminas para frangos de corte: Revisão sistemática e metanálise

Abstract

The advancement of genetic selection enabled fast-growing broiler lines to be developed. Consequently, the embryonic phase of these birds came to represent a significant part of their total life. The embryonic development of birds is dependent on the nutritional content of the egg. However, this may no longer be sufficient to meet the demand for nutrients from embryos with higher genetic potential, this can negatively influence the development of these animals both during incubation and after hatching. Therefore, measures aimed at modulating embryonic development, such as the in ovo supply of nutrients, become necessary. Thus, the objective of the present study was to elaborate a systematic review and meta-analysis to evaluate the effects of in ovo inoculation of vitamins on hatchability and post-hatching performance of broiler chickens. The search for scientific articles was conducted in June 2022, in eight databases (Embase, Google Scholar, Scielo, Science Direct, Scopus, Periodicos Capes, PubMed and Web of Science), using the combination of keywords (vitamin OR vitamins) AND "in ovo" AND (broiler OR broilers) in the first search. In the second search, a combination was made for each type of vitamin: (categorization of vitamin OR vitamin name) followed by the keywords AND "in ovo" AND (broiler OR broilers). From a total of 9,573 articles returned, 45 were selected and evaluated for quality criteria. The meta-analysis was performed using the random effects model to obtain the confidence interval (CI) of the differences between the averages of the groups inoculated with vitamin and control group (diluent injection), except for the hatchability variable, for which the effect estimate was evaluated by Odds Ratio. Publication bias was performed using the funnel plot. Among the selected articles, six received a maximum score of 20 points. Regarding the quality of evidence, 84% of the articles were classified as highest quality, with remainder as intermediary evidence. In general, in ovo inoculation of vitamins did not influence (P>0.05) the hatchability and hatching weight, but increased (P<0.01) weight gain and improved (P<0.05) feed conversion post-hatching. In the subgroup analysis, greater weight gain and better feed conversion were obtained (P<0.05) with ascorbic acid and biotin. Folic acid and thiamin increased (P<0.05) only weight gain. On the other hand, riboflavin administration reduced (P<0.01) hatchability, while thiamin and pyridoxine reduced (P<0.05) hatching weight. Tocopherol increased (P<0.01) feed intake. It is concluded that in ovo inoculation of vitamins is able to improve the post-hatching performance of broilers, without influencing the hatching parameters. The best results were achieved with ascorbic acid, biotin and folic acid.