VetSRev
Database of veterinary systematic reviews
Database of veterinary systematic reviews
Animal Production Science (2021) 61: 621–629
DOI: 10.1071/AN20628
Appropriate supplementation of trace minerals is fundamental to enhance the metabolic status of growing animals and promote an adequate expression of genetic potential. Zinc (Zn) is an essential mineral fundamental in many biological processes that are related to growth, energy balance and immunity. The aim of the present study was to analyse the effect of Zn supplementation on growth parameters in small ruminants by using a meta-analytic approach. Sources of heterogeneity were explored using a meta-regression analysis. The final database was integrated from a total of 53 trials. Only indexed articles that provided an effect size measure, variability measure, sample size and randomisation of the procedure were considered. The dependent variables considered for the study were average daily gain (ADG), dry-matter intake (DMI), feed conversion ratio (FCR), final bodyweight, and glucose blood concentration. The exploratory variables included species (sheep and goat), breed, production level, Zn source and dosage. The ’meta’ package in R statistical software was used to conduct the meta-analyses. For response variables that showed substantial heterogeneity (I^\textrm2 \textgreater 50%), mixed-effect models (meta-regression analysis) were constructed to explore the sources of heterogeneity using the ’Metafor’ package. DMI was higher in animals supplemented with Zn (\textgreater21.08 g/day, P = 0.0001). Breed, species, production level, and dosage reduced heterogeneity of DMI response from I^\textrm2 = 84.8 to I^\textrm2 = 48.1%. Zn-supplemented animals showed higher ADG (17.39 g/day, P = 0.001), which was affected by species, breed dosage and Zn-source. Zn supplementation improved feed efficiency, with lower values of FCR (-1.56 g/g, P \textless 0.0001). There was a positive relationship between the dosage and effect size in all outcome variables (P \textless 0.05). Zn-proteinate showed the best response in both species to ADG, FCR and final body weight. Our findings of the systematic review concluded that dietary Zn supplementation improves growth performance in small ruminants and their level of response is influenced mainly by species, production level, and Zn-source and dosage.
Angeles-Hernandez, J. C., Miranda, M., Munoz-Benitez, A. L., Vieyra-Alberto, R., Morales-Aguilar, N., Paz, E. A., & Gonzalez-Ronquillo, M. (2021). Zinc supplementation improves growth performance in small ruminants: a systematic review and meta-regression analysis. Animal Production Science, 61(7), 621–629. https://doi.org/10.1071/AN20628 meta-analysis, ruminants, Animal Nutrition (Production Responses) [LL520], liveweight gain, liveweight gains, systematic reviews, Animal Nutrition (Physiology) [LL510], diets, feed conversion, body weight, data analysis, microelements, minerals, trace elements, blood chemistry, feeding stuffs, feeds, analysis, growth rate, sheep, sheep feeding, feed conversion efficiency, feed intake, feed supplements, goat feeding, performance, databases, blood sugar, goats, data banks, Feed Composition and Quality [RR300], zinc, blood glucose, glucose in blood, mineral supplements, energy balance