Interaction Between Dietary Lipid Level and Seasonal Temperature Changes in Gilthead Sea Bream Sparus aurata: Effects on Growth, Fat Deposition, Plasma Biochemistry, Digestive Enzyme Activity, and Gut Bacterial Community

Abstract

A 121-day feeding trial was undertaken to test the effects of two dietary lipid levels (16 and 21% L16, L21) in triplicated gilthead sea bream groups (initial weight: 67.5 g) reared at two different water temperatures (high, H 23°C and low, L 17°C) in the same recirculation system but exposed to a switch in temperature after 58 days. Fish kept at H were transferred to L (HL transition, autumn shift), and the fish kept at L were exposed to H (LH transition, summer shift), while continuing to receive the same diet to apparent satiation in each group. At the end of the trial, no significant diet effect on specific growth rate (SGR), feed intake (FI), and feed conversion rate (FCR) were detected in fish exposed to HL transition compared with those exposed to LH transition, while gross lipid efficiency (GLE) and lipid efficiency ratio (LER) were higher in L16. After temperature changes, L16 displayed higher SGR, FI, GLE, and LER, while mesenteric fat index was reduced. After temperature changes, the combined effects of low lipid diet and low temperature conditions resulted in higher pepsin activity, while trypsin, chymotrypsin, and lipase activities were generally higher at high lipid content. The combined effect of diet and temperature did not alter the metabolic plasma profile, except for the observed final higher aspartate aminotransferase (AST) and alkaline phosphatase (ALP) values when combining high dietary lipid (L21) and temperature changes. Different diets showed a significantly different gut microbiome layout, only at high temperature with L16 diet resulting in a higher load of Lactobacillus. On the contrary, no dietary impact on ecosystem diversity was observed, independently from the temperature. In addition, L16 diet in the HL transition favored an increase in Weissella and Bradyrhizobium genera in the gut microbiome, while in the final condition of LH transition, L21 diet favored a significant increase in Streptococcus and Bacillus. According to the results, the utilization of 16% dietary lipid levels in gilthead sea bream should be preferred during seasonal temperature changes in order to optimize feed utilization and gut health.

Biochemical features and modulation of digestive enzymes by environmental temperature in the greater amberjack, Seriola dumerili

“…Within the temperature tolerance range, many studies have been also performed on the effects of temperature on growth, physiological responses, and health of farmed fish, including the effects of seasonal thermal changes (Pelusio et al, 2021). However, for relatively novel species for the aquaculture industry this information is rather limited.…”

The Effect of Dietary Lactic Acid Bacteria on Intestinal Microbiota and Immune Responses of Crucian Carp (Carassius auratus) Under Water Temperature Decrease

“…Hence, water temperature is a determinant environmental factor for species that are highly susceptible to temperature changes. Water temperature plays a crucial role in nutrient utilization, metabolism, and regulation of gut microbiota ( Sánchez-Nuño et al, 2018a ; Pelusio et al, 2021 ). Variations in temperature shape the composition of fish gut microbiota, particularly in lineages of Firmicutes and Proteobacteria ( Mateus et al, 2017 ).…”

Midgut bacterial microbiota of 12 fish species from a marine protected area in the Aegean Sea (Greece)

“…In the gilthead seabream, Bradyrhizobium, along with the known probiotic Weissella, was favoured after a transition from a high-to low-lipid diet [Pelusio et al 2021]. Bradyrhizobium has not been reported to be associated with fish disease, but it has been found to be sensitive to Vibrio harveyi infection [Deng et al 2020].…”

“…Bradyrhizobium has been found to co-dominate with known probiotic bacteria in the midgut of the olive flounder Paralichthys olivaceus under experimental conditions [Niu et al 2020]. In the gilthead seabream, Bradyrhizobium , along with the known probiotic Weissella , was favoured after a transition from a high- to low-lipid diet [Pelusio et al 2021]. Bradyrhizobium has not been reported to be associated with fish disease, but it has been found to be sensitive to Vibrio harveyi infection [Deng et al 2020].…”