Portal de Pesquisa da BVS Veterinária

Acta sci. vet. (Impr.); 41: Pub. 1109, 2013. tab

Artigo em Inglês | VETINDEX | ID: biblio-1372556

Resumo

Background: Carotenoids such as ß-carotene, α-carotene, lycopene, lutein and ß-cryptoxanthin are a family of pigmented compounds which are synthesized by many vegetable crops and microorganisms but not animals. In human and murine models, carotenoids are shown to mediate their effects via different mechanisms such as gap junction communication, cell growth regulation, modulating gene expression and immune response. In some fish species, the immunomodulating action of synthetic carotenoids has been the subject of some research. How ever, studies on the effects of carotenoids from natural sources on fish growth performance and immune parameters are lacking. In the current study, a preliminary study with 60 days feeding was conducted to study the influence of different natural sources of carotenoids from some vegetable crops on growth and some immune indices in rainbow trout (Oncorhynchus mykiss). Materials, Methods & Results: Purified isonitrigenous (crude protein: 40.16%) and isocaloric (3660 kcal kg-1) diet with 4.5 g of powdered crops namely tomato (Solanum lycopersicum) and sweet pepper (Capsicum annuum) per kg feed or control diet without any treatment was prepared. Rainbow trout weighing 150 ± 9 g were distributed equally into 2 groups with 33 fish in each group. Each group contained 11 fish in triplicate reared in individual ponds. In treatment group, fish were fed diet containing 4.5 g of powdered crops for 60 days while in control group, basal diet without any treatments was fed. At the end of the feeding trial, 4 fish per tank were sampled to analyze the growth parameters. Seven fish were also bled from the caudal vein to collect serum sample for immune parameters. During this study no mortality of fish was observed in different groups. Results of this study showed that condition factor and feed intake were similar among the groups while specific growth rate and weight gain showed a significant increase in treatment group compared to control group. Immunological parameters namely peroxidase content, antibacterial activity, α1-antiprotease, total antiprotease activities and total protein did not vary among the groups, even though slight decrease in serum peroxidase content was shown in treatment group. On the other hand, serum lysozyme activity of fish fed treatment diet was significantly higher than control group. Discussion: Enhanced growth performance in the current study might be attributed to some intermediary metabolism which could enhance nutrient utilization and may ultimately result in improved fi sh growth. Lysozyme is secreted by leukocytes and is a marker of leukocyte activity, increasing concomitantly with phagocytic activity. Administration of natural carotenoids in fish diet exerts a stabilizing or protective effect against oxidative damage, and enhances the proliferation of these cells, which could result in increased serum lysozyme level. Feeding natural carotenoids might act as a direct scavenger of reactive oxygen species and decrease the body's need for certain antioxidant enzymes. Therefore, slight decrease in serum peroxidase content can be attributed to this point. In conclusion, this study showed that rainbow trout appear to benefit from inclusion of crops in diet in terms of improved growth performance and immune system.

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