No abstract

The demand for products to replace high-cost raw materials, such oil and fish meal, in the manufacture of feed for use in aquaculture, while also guaranteeing the nutritional quality of the diets, is increasing. Silage produced with fish and vegetables residues is a low-cost and efficient protein source. The objective of the present study was to evaluate the physiological and biochemical responses of tambaqui fingerlings fed four different levels of silage included in commercial feed with 28% crude protein, over two periods: 45 and 90 days. Each treatment was carried out over three replications, with 10 tambaqui in each 100 L experimental tank. At the end of each established period, blood samples were collected from five animals from each repetition to determine the hematological and biochemical variables. Body weight and total length, hepatosomatic and liposomal indices and hematocrit of specimens fed with diets supplemented with silage did not exhibit significant changes in both assessment period. After 45 days of feeding, the hemoglobin concentration increased when tambaqui were fed a diet including 20% silage. The red blood cell count, mean corpuscular volume and mean corpuscular hemoglobin did not change between treatments in either period. The total protein concentrations increased significantly in the plasma of tambaqui fed with diets with the inclusion of 5 and 10% of silage, evaluated after feeding for 45 days. It was found that the groups which had silage included in their diet did not exhibit significant alterations in the evaluated parameters, and the diet was therefore not consider harmful to the health of tambaqui. Therefore, the use of silage as a feed supplement during tambaqui farming is a sustainable alternative for producers, as it leads to a reduction of impacts of fish and vegetables waste disposal.

SummaryHoplias malabaricus and Hoplerythrinus unitaeniatus are Erythrinidae family widely distributed in the Amazon River system of great value to both commercial and subsistence fishing for riverine populations. As such, the objective of the present study was to investigate the endoparasite communities of H. malabaricus and H. unitaeniatus of a tributary of the Amazon River in the north of Brazil. The endoparasite communities of H. unitaeniatus and H. malabaricus were taxonomically similar (85%) and consisted of Clinostomum marginatum, Contracaecum sp., Guyanema seriei seriei, Procamallanus (Spirocamallanus) inopinatus, Pseudoproleptus sp. and Gorytocephalus spectabilis, although the dominant endoparasite was C. marginatum, which was the most prevalent and abundant. All the specimens of both H. malabaricus and H. unitaeniatus were parasitized, with a total of 1237 helminths collected in the former host and 1151 helminths collected in the latter. Hoplerythrinus unitaeniatus possessed greater parasite species richness. Both hosts had an aggregate dispersion of parasites, and the abundance of C. marginatum, Contracaecum sp. and G. spectabilis correlated positively with the weight and length of the hosts. The condition factor was not affected by parasitism, but the abundance of C. marginatum and Contracaecum sp. increased when the condition factor of the hosts decreased. This is the first report of G. seriei seriei for H. malabaricus and Pseudoproleptus sp. for H. unitaeniatus.

No abstract

A substituição parcial da ração comercial para peixes por um preparado de soja e milho cozidos na alimentação de híbridos tambatingas, realizado em uma piscicultura no Município de Macapá, Estado do Amapá, pode promover redução dos custos de produção para o piscicultor. Esta prática é muito utilizada pelos produtores no estado, entretanto, o crescimento e a condição de saúde desses peixes devem ser monitorados durante o cultivo, o qual foi o objetivo do presente estudo. Avaliações biométricas e fisiológicas (hematológica e bioquímica) foram realizadas nos peixes, além do monitoramento da qualidade da água sendo a primeira análise, dois meses após o início da alimentação (RC I e RSM I), e a segunda, após quatro meses (RCM II e RSM II). A substituição da ração comercial não causou alterações no pH, temperatura e concentração de oxigênio dissolvido da água dos viveiros da piscicultura; entretanto, alterações fisiológicas ocorreram nos peixes. Os híbridos tambatingas apresentaram crescimento e ganho de peso (P<0,05) quando alimentados com o preparado de soja e milho (RSM), além disso, ocorreram alterações nos níveis de hemoglobina nas células sanguíneas e nos níveis plasmáticos de proteína e ureia. O leucograma dos híbridos indicou redução no número de células brancas no sangue periférico, podendo indicar presença de processo infeccioso nos peixes. Conclui-se que o produtor obteve redução no uso de ração comercial para apenas 20% do total, diminuindo os custos de produção de tambatingas. Entretanto, estudos a longo prazo (no mínimo dez meses) são necessários, possibilitando monitoramento da saúde desses animais.