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Innovation in aquaculture nutrition is linked to the use of new compounds, in order to achieve a more sustainable production. The grapefruit industry is one of the biggest in the fruit sector due to the enormous wine and juice production. As a consequence, tons of grape bagasse (GB) turn into waste every year, a product rich in antioxidants such as polyphenols (PPS). Shrimp Litopenaeus vannamei is generally cultured under stressful conditions such as crowding, which can increase the production of reactive oxygen species (ROS) and could benefit from feed with functional properties. Five isoproteic and isolipidic diets were formulated: GB0, GB2.5, GB5, GB10 and GB15% of GB inclusion; those diets were tested in triplicate. Shrimp juveniles (0.35 ± 0.01 g) were stocked at a density of 150 shrimp m−3, and fed for 45 days. At the end of the experimental period, hepatopancreas and muscle samples of shrimp were collected for the determination of the antioxidant capacity against peroxyl radicals (ACAP), thiobarbituric acid‐reactive substances (TBARS) and PPS content. The results indicate that it is possible to add up to 2.5% of GB inclusion without affecting growth and feed conversion rate significantly. Also, the shrimps muscle of the GB15 treatment presented the highest PPS concentration and the lowest lipid peroxidation. In conclusion, it is possible to include GB in shrimp diets in small amounts, despite not obtaining significant antioxidant benefits. [ABSTRACT FROM AUTHOR]

This study investigated the effects of the inclusion of Mauritia flexuosa fruit pulp in the diet on the growth performance, economic benefit, muscle composition, total contents of carotenoids and flavonoids, chromaticity parameters, total antioxidant capacity, and lipid peroxidation in the hepatopancreas and muscle of the juvenile shrimp Litopenaeus vannamei (weighing 1.26 ± 0.023 g). Five diets (37% protein, 10% lipid) consisting of 0 (control), 1.25%, 2.50%, 5.00% and 10.00% (w/w) M. flexuosa fruit pulp were formulated and provided to the shrimps (n = 50 per tank, treatments in triplicate) for 31 days. Results showed that there were no significant differences between the treatments in terms of the growth capacity, chromaticity parameters, muscle composition and total flavonoid content of shrimps (p >.05). However, the carotenoid content in the muscle and hepatopancreas of the shrimps was significantly increased due to the dietary carotenoids present in M. flexuosa fruit pulp (p <.05). This increase in the carotenoid content directly favoured the increase in the antioxidant capacity in the hepatopancreas and muscle of the shrimps (R2 = 0.99 and R2 = 0.97 respectively; p <.05). There was also a direct relationship between the carotenoid content and the decrease in lipid peroxidation in the hepatopancreas (R2 = 0.90; p <.05). The feed cost kg−1 in terms of weight gain and protein production decreased with the inclusion of high levels of M. flexuosa fruit pulp, reaching 8.11% and 18.76% of cost reduction, respectively, with the addition of 5.00% of M. flexuosa fruit pulp. Therefore, the inclusion of M. flexuosa fruit pulp in the diets of shrimp can increase the carotenoid content and the antioxidant capacity in the hepatopancreas and muscle, reduce lipid peroxidation in the hepatopancreas, and probably provide economic benefits for the rearing of juvenile shrimps. [ABSTRACT FROM AUTHOR]

This study investigated the effects of the use of the inclusion of açaí on the diet of shrimp Litopenaeus vannamei on antioxidant and histopathological responses after exposure to ammonia. The shrimps were fed two experimental diets: control and with 10% of açaí inclusion (W/W), for 35 days. Afterwards, the organisms were exposed at four concentrations of ammonia (0.01‐control; 0.26; 0.48 and 0.91 mg NH3‐N L−1) for 96 hr. The total antioxidant capacity (ACAP) of the gills decreased significantly in both diets when exposed to ammonia, whereas in the muscle, the açaí promoted an increase in ACAP. Concomitantly, lipid peroxidation levels increased in the gills and decreased in muscle. After exposure to ammonia, glutathione‐S‐transferase activity increased in hepatopancreas in shrimps fed with açaí facilitating the detoxification of lipid peroxidation by‐products, and the concentration of protein sulfhydryl groups decreased in the gills and muscle of the shrimp of the control diet, evidencing protein damage, an unobserved response in shrimps that received the açaí diet. Histopathological changes decreased in açaí‐fed shrimps about the control diet after exposure to ammonia. It is concluded that açaí mitigated ammonia‐induced histopathological changes, improved the antioxidant defence system (gills and muscle) and attenuated the lipid damage in the muscle. [ABSTRACT FROM AUTHOR]

This study evaluated the effects of dietary supplementation with different concentrations of chitosan from shrimp tailings on the antioxidant and immune systems of juvenile Litopenaeus vannamei cultivated in a biofloc system (BFT) and subjected to abrupt salinity reduction. The experiment was performed with juvenile shrimp fed diets supplemented with four levels of chitosan: C0 (0 g kg−1 diet – control), C1 (1 g kg−1 diet), C3 (3 g kg−1 diet), and C5 (5 g kg−1 diet). After 35 days, the shrimp were exposed to an acute reduction in salinity from 30 to 5 for 24 h, and the hemolymph, gills, and hepatopancreas were collected. No significant differences were found in the growth performance and survival among treatments. In the gills, acute salinity reduction increased the activity of catalase (CAT), although this effect was reversed by the 5 g kg−1 diet (C5). Furthermore, glutathione-S-transferase (GST) activity was maintained at the basal level in shrimp fed a 1 g kg−1 diet (C1) but reduced in those fed C3 and C5. We also identified a reduction in lipid peroxidation in shrimp fed the C3 and C5 diets. In the hepatopancreas, the GST activities and glutathione (GSH) levels were higher in shrimp supplemented with chitosan, which showed a protective effect. Saline stress and chitosan supplementation did not affect differential hemocyte counts. In conclusion, the results of this study suggest that dietary intake of chitosan could enhance some antioxidant defenses of L. vannamei farmed in a BFT system. Thus, the inclusion of at least 1 g kg−1 chitosan could represent a good alternative to improve defense mechanisms and stress resistance, and it could also contribute to the development of sustainable aquaculture. • Salinity stress induced oxidative stress in shrimp cultivated in the BFT system. • Chitosan supplementation improved different antioxidant responses in both the gills and hepatopancreas of L. vannamei. • Chitosan reduced lipid peroxidation in the gills of shrimp subjected to salinity stress. [ABSTRACT FROM AUTHOR]