Efeito da frequência alimentar sobre o crescimento do Lambari, Astyanax bimaculatus (Characiformes, Characidae)

Abstract

Among the native species with zootechnical potential for aquaculture, the lambari, Astyanax bimaculatus, has stood out with desirable characteristics for cultivation, in addition to the growing commercial acceptance as food and live bait for sport fishing. Thus, studies regarding the ideal amount of food are necessary for a better zootechnical performance of the species. Thus, this research aimed to evaluate and describe the influence of food frequency on the growth of A. bimaculatus. For the development of the research, matrices of A.bimaculatus were captured in a fish farm in Maranhão and taken to the Laboratory of Reproduction of Aquatic Organisms - LARAQUA, these specimens after the adaptation process were submitted to hormonal induction using a synthetic hormone in doses consistent with their body weight, then couples were stored in a spawning system composed of 4 basins (20 liters each) with constant aeration of blowers, where the semi-induced spawning occurred. After hatching, the post-larvae were transferred to a nursery tank, where they underwent food training with commercial feed for a period of 20 days. Subsequently the fry were submitted to biometrics and transferred to the experimental units where they received the pre-established treatments. Water monitoring was performed weekly using a digital Aksoak 88 multi-parameter and colorimetric meters for nitrite and ammonia. The results showed that the natural food together with the commercial feed 45% CP significantly influenced the development of the fry, presenting good initial indexes of weight and length. The physical-chemical parameters of the water remained within acceptable standards for the species throughout the research, and the zootechnical indices showed linear growth in relation to the increase in food frequencies. It was concluded that the growth of A. bimaculatus is influenced by the feeding frequency. Considering the best weight gain, we can indicate that the fingerlings of A. bimaculatus can achieve the best zootechnical performance when fed four times a day. However, it is worth mentioning that the increase in food frequency favored a higher feed conversion, as well as a greater demand for labor, emphasizing the need for an evaluation of all productive activity.