Impacts of microplastics on reproductive performance of male tilapia (Oreochromis niloticus) pre-fed on Amphora coffeaeformis.

This study examines the potential defending effects of the diatom, Amphora coffeaeformis, as a feed additive versus the deleterious effects (mainly on gonads) caused by microplastics (MPs) in Nile tilapia, Oreochromes niloticus. Groups of male tilapia were pre-fed diets with four different supplementation levels of A. coffeaeformis (0%, 2.5%, 5%, and 7.5%) for 70 days, then exposed to 10 mg/L MPs for 15 days. Thereafter, samples were taken from the four experimental groups and the control fish group, for evaluating blood picture, erythrocytes alterations, biochemical parameters, catalase (CAT), superoxide dismutase (SDO), and total antioxidant capacity (TAC). In addition, male reproductive performance was assessed by quantifying the follicle-stimulating hormone (FSH), luteinizing hormone (LH), and testosterone (T), also testicular sections and GSI% were also assessed. The results showed that the number of leucocytes were significantly (p < 0.05) higher, but the number of red blood cells (RBCs), the level of Hemoglobin (Hb), the percentage of Hematocrit (Ht), the number of platelets, and the eosinophil percentages were significantly decreased (p < 0.05) when fish exposed to MPs. Biochemical parameters (ALP, glucose, uric acid, albumin, and A/G ratio) were significantly increased after MP exposure compared with the control group. Furthermore, MPs induced a significant decline in both serum LH and T levels. Testicular, histological, degenerative changes and testis-ova were found in the MP-exposed fish. Thus, A. coffeaeformis supplementation displayed ameliorative properties that detoxified the negative effects of MPs. This study provides a better understanding of the reproductive injuries caused by MPs exposure and evidence for the use of A. coffeaeformis as a natural remedy in freshwater tilapia.

Assessment of sesame meal as a soybean meal replacement in European sea bass (Dicentrarchus labrax) diets based on aspects of growth, amino acid profiles, haematology, intestinal and hepatic integrity and macroelement contents.

An 87-day feeding trial was carried out to assess the use of dehulled and defatted sesame seed meal (SM) as a partial dietary replacement for soybean meal (SBM) at 0%, 15%, 30% and 45% (SM0, SM1, SM2 and SM3, respectively) in juvenile sea bass stocked in 12 tanks (0.5 m3) and with an initial weight of 24 ± 0.50 g. All diets were isonitrogenous (~ 47% crude protein), isoenergetic (~ 22 MJ/kg) and tested in triplicate. The lowest growth and feed utilization efficacy were detected in fish fed the SM3 diet; moreover, diets with a lower SM content did not have significant effects relative to the CTR diet. Fish biochemical analysis indicated a gradual decrease in carcass protein content coinciding with an increase in lipid deposition and viscerosomatic index values as the SM level in the diet increased. The macroelements' (P, Na and K) fish contents did not differ significantly among groups. The SM3 group had the lowest Ca and highest Mg contents among the experimental groups. The fish amino acid profile indicated slight alterations in essential amino acid percentages among groups. Haematological analysis and serum biochemistry indicated that using SM at a content of up to 30% had limited negative impacts on fish health. Liver histological inspection indicated that higher levels of SM led to severe hepatocyte infiltration with slight signs of necrosis in fish fed SM3 diet. Intestinal histological examinations indicated that the distal portion of the intestine was the portion most affected by SBM replacement with SM with signs of intestinal inflammation in SM3 group.