Hortelã-pimenta (Mentha piperita) e alecrim (Rosmarinus officinalis) como aditivo alimentar em dietas para tilápia do nilo

Abstract

The inclusion of plant extracts in fish diets can be a promising alternative due to their different forms of action on the animal organism. Prophylactic strategies applied to fish nutrition have been tested as immune stimulants, to improve performance, reduce stress, increase resistance to diseases, improve the health of the gastrointestinal tract, and thus improve the efficiency of the nutrients present in the feed. This study aimed to evaluate the effects of peppermint (Mentha piperita) and rosemary (Rosmarinus officinalis) at increasing levels in the commercial diet of Nile tilapia post-larvae on zootechnical performance and survival. 900 Nile tilapia post-larvae with an average initial weight of 20.3 ± 2.3 mg and a total length of 11.28 ± 0.55 mm were used, distributed in a completely randomized design, consisting of a five of treatments (0; H-1; A-1; H-1/A-1; H-1.5/A-1.5%) of essential oil and three replications, 60 fish were housed per experimental unit with a useful volume of 100 liters with a recirculating water system. Final weight (g), total length (cm), final biomass (g), weight gain (g), average daily weight gain (g/day), feed consumption, feed conversion, specific growth rate, and survival (%) were evaluated. The physicochemical variables of the water remained within the acceptable values for rearing the species. There was a significant difference between the treatments (p<0.05) for the zootechnical performance parameters evaluated and for survival. The values obtained show that the addition of 1% rosemary essential oil to the diet of Nile tilapia post-larvae promoted significant improvements in final weight, final biomass, weight gain, specific growth rate, and average daily weight gain. The addition of a mix of peppermint and rosemary essential oils in proportions of 1:1% and 1.5:1.5% led to lower zootechnical performance and lower survival.