Coping with suboptimal water temperature: modifications in blood parameters, body composition, and postingestive-driven diet selection in Nile tilapia fed two vegetable oil blends

The world tilapia production faces seasonal variations. However, very few nutritional studies have addressed suboptimal temperature. We evaluated the effect of two temperatures (20 or 30 °C) and two vegetable oil blends (one rich in corn oil (COR) and one rich linseed oil (LIN)) on tilapia growth, body composition, and blood parameters using a 2 × 2 factorial design with the following treatments: COR-20; LIN-20; COR-30; LIN-30 (Trial 1). In addition, we also evaluated the effect of postingestive signals of dietary oils when the organoleptic properties of diets were isolated (Trial 2). In the Trial 1, 256 fish (15.36 ± 0.14 g) were placed in 16 aquariums and submitted during 30 days to the 2 × 2 factorial designs: COR-20; LIN-20; COR-30; LIN-30. The temperatures were established in two independent water recirculation systems. In the Trial 2, 96 fish (34.02 ± 0.79 g) were placed in 12 aquariums and subjected to the same experimental design of Trial 1, but to evaluate fish feeding behavior. They were allowed to select the encapsulated diets provided in different feeding halls to evaluate if diet preferences are influenced by postingestive signals. As the Trial 1 results show, diets had no significant effects on growth, dietary protein use, and body centesimal composition, but 30 °C induced the best performance and protein deposition (P < 0.05). LIN-20 showed lower very-low-density lipoprotein and cortisol, but higher high-density lipoprotein (HDL), aspartate aminotransferase (AST), alanine aminotransferase (ALT), and triglycerides (TG) than COR-20 (P < 0.05). COR-30 presented higher HDL, AST, ALT, TG, and cortisol than LIN-30. The fish fed COR showed lower C20:5n-3 (EPA) and higher n-6 than fish fed LIN (P < 0.05). The fish fed LIN had high n-3 highly unsaturated fatty acid. ∑ polyunsaturated fatty acid was higher at 30 °C. Finally, the tilapia in Trial 2 showed clear diet intake regulation and preference for LIN (P < 0.05), regardless of temperature. In short, lipid sources had no influence on tilapia performance; however, temperature affects carcass lipid deposition as well as fatty acids profile. Notably, the preference for linseed oil can suggest nutritional metabolic issues, contributing to animal behavior knowledge

Abelhas (Hymenoptera: Apoidea) visitantes das flores do feijão guandu no Recôncavo Baiano, Brasil Bees (Hymenoptera: Apoidea) on pigeonpea flowers in 'Recôncavo Baiano' region, Brazil

O feijão guandu Cajanus cajan L. é uma cultura comum, encontrada com freqüência em todo o Brasil, principalmente em pequenas propriedades rurais. Este trabalho teve por objetivo obter informações sobre a diversidade de abelhas visitantes das flores do feijão guandu, gerando informações sobre a estrutura da comunidade de abelhas e a importância desta leguminosa como fonte de recursos tróficos. As coletas foram feitas semanalmente, entre maio e outubro de 2005, na área experimental de Entomologia do Centro de Ciências Agrárias da UFBA, localizada no município de Cruz das Almas, Bahia, no intervalo entre as 6:00 e as 18:00 horas. Um total de 4.676 indivíduos foi coletado visitando as flores do feijão guandu. A família Apidae foi representada por 99,3% dos indivíduos e 76,2% das espécies amostradas. Os gêneros Xylocopa e Trigona foram os que apresentaram maior riqueza, com quatro e três espécies, respectivamente. Trigona spinipes foi a espécie mais abundante, com freqüência relativa igual a 83,1%, seguida de Nannotrigona testaceicornis (5,1%).<br>Pigeonpea, Cajanus cajan L. is a common crop, frequently found throughout Brazil, mainly in small rural properties. This research was aimed at geting information on the diversity of visiting bees to flowers of pigeonpea, generating information on the structure of the bee community and the importance of this Leguminosae as source of food resources. Collections had been made weekly, between May and October 2005 in the Experimental area of the Center of Agrarian Sciences and Environmental of the UFBA, located in the Cruz das Almas, Bahia, in the interval between 6:00 AM and 06:00 PM. A total of 4.676 individuals was collected visiting the pigeonpea flowers. The Apidae family was represented by 99.25% of individuals and 76.19% of total species. The genera Xylocopa and Trigona were the ones that showed greater richness, with four and three species, respectively. Trigona spinipes was the most abundant species, with relative frequency of 83.1%, followed by Nannotrigona testaceicornis (5.1%)