ABSTRACT
Black Soldier Fly (BSF) meal is considered an alternative, emerging, and sustainable ingredient for aquafeed formulation. However, results on fish physiological responses are still fragmentary and often controversial, and no data are available on the effect of insect meal-based diets on fish reproduction. On this regard, zebrafish, with its relatively short life cycle, represents an ideal experimental model to explore this topic. In this study, female zebrafish were fed for 12 months on a control diet based on fish meal (FM) and fish oil and two experimental diets with full-fat BSF (Hermetia illucens) prepupae meal inclusion, to replace 25% and 50% of FM (BSF25 and BSF50). All diets were isonitrogenous, isolipidic, and isoenergetic. The effects of these two experimental diets on female's reproduction were investigated through a multidisciplinary approach, including the evaluation of growth, gonadosomatic index, spawned/fertilized eggs and hatching rate, adult female carcass and fertilized egg fatty acid composition, histological analysis of the ovary, spectroscopic macromolecular composition of class IV oocytes, and expression of genes involved in fish lipid metabolism in the liver. Results showed that while fish were perfectly able to cope with a 25% insect meal dietary inclusion, a 50% inclusion level caused the overexpression of genes involved in lipid metabolism, a general reduction in the number of spawned eggs, and differences in the frequency rate of previtellogenic oocytes, class III, IV, oocytes and postovulatory follicles and atretic oocytes, in the macromolecular composition of class IV oocytes, and in the fatty acid composition of the fertilized eggs, respect to control and 25% group.
Subject(s)
Diet , Insecta , Reproduction/drug effects , Zebrafish/physiology , Animal Feed/analysis , Animals , FemaleABSTRACT
The giant mottled eel is a species with high commercial value so overfishing, river management, and water pollution have negatively affected its movement and population numbers. Anguilla marmorata (eel) was listed in the Vietnam Red Data Book 2007 with a description of Vulnerability. This study used a barcode technique to analyze molecular characteristics and build genetic plants based on the cytochrome c oxidase I gene segment isolated from the mitochondrial genome of 48 individuals of A. marmorata collected in five different ecological regions of Thua Thien Hue, Vietnam. The isolated the cytochrome c oxidase I sequence has a length of 843 nucleotides, four base nucleotides of 30.03% Thymine, 25.15% Cytosine, 27.49% Adenine, and 17.43% Guanine. The percentage of Guanine + Cytosine content (42.58%) is acceptable, lower than the Adenine + Thymine content. The replacement capacity of Adenine and Guanine is 22.45% highest, the ratio between Thymine and Guanine; Cytosine and Guanine are the lowest at 2.72%. The establishment of genetically modified plants has shown the high genetic similarity of individuals in eel populations in Thua Thien Hue. The population of Anguilla marmorata eels in Thua Thien Hue, Vietnam is divided into two separate groups that are guided by the migration process and specific ecological. This is particularly important in building strategies to conserve and develop the gene for eel in Vietnam and Thua Thien Hue.
