Diferentes níveis protéicos na dieta de girinos de rã-touro (Lithobates catesbeianus) e seus efeitos sobre o tecido hepático

Abstract

RESUMO.-Para verificação da ocorrência de alterações morfológicas no fígado, foram coletados dez animais de cada dieta, no 30º dia (1º período experimental) e no 60º dia (2º período experimental), sendo esse, o último dia do período experimental e início do clímax da metamorfose. Os girinos foram distribuídos em delineamento experimental inteiramente casualizado (DIC) com três tratamentos: dieta experimental com 32,68% de proteína bruta e duas dietas comerciais com 37,92% e 57,53% de proteí-na bruta. Os órgãos coletados foram fixados em solução de Bouin e depois submetidos às práticas da rotina histotecnológica e coradas com hematoxilina -Eosina (HE). Na avaliação microscópica do fígado foram encontradas diversas alterações morfológicas como: Desorganização e vacuolização de hepatócitos, infiltrado inflamatório mononuclear periportal, multifocal e difuso, infiltrado inflamatório eosinofílico, congestão, hemorragia, hemólise e necrose. As alterações hepáticas encontradas neste estudo sugerem que as dietas utilizadas para os girinos de rã-touro, não atenderam suas necessidades dietéticas, afetando a homeostasia dos mesmos, comprometendo assim, sua sanidade. To verify the occurrence of liver morphological changes, bullfrog tadpoles were fed three diets: an experimental diet with 32.68% crude protein and two commercial diets with 37.92% and 57.53% crude protein. Tadpoles were distributed into a completely randomized design (CRD) with three treatments and four replications. Liver samples were collected twice, on the 30th and 60th day of the experiment. Tadpole livers were fixed in Bouin's solution, then subjected to routine histotechnology procedures, and stained with hematoxylin -eosin (HE). Microscopic evaluation of liver tissue showed several morphological changes like disorganization and vacuolization of hepatocytes; periportal, multifocal and diffuse mononuclear inflammatory infiltrate, eosinophilic inflammatory infiltration, congestion, hemorrhage, hemolysis and necrosis. The liver changes found in this study suggest that diets used for bullfrog tadpoles, did not meet their dietary needs, what affected their homeostasis, thus compromising their health.

Feeds formulated with alternative ingredients for bullfrog tadpoles (Lithobates catesbeianus)

“…The average pH values obtained throughout the study showed little variation between treatments. A pH range between 6.0 and 7.0 is considered ideal for bullfrog tadpoles (Mansano et al, 2016).…”

“…In addition, this substitution of ingredients did not affect the quality in the zootechnical performance of the animals, even more when dealing with a minutely critical phase such as that of tadpoles, where food is fundamental for the health, proper development, and metamorphosis of the animal (Mansano et al, 2016). In turn, a reduction in the cost of the diet and increased production could enhance profits for frog breeders significantly and make the strategy viable.…”