Aquaculture Nutrition最新文献

To further explore the impact of nutrient fortification on the ovarian secondary development of redclaw crayfish, four groups were set up: group ①, no feeding; group ②, formulated feeding; groups ③ and ④, formulated feed + nutrient bait. Results showed (1) the proportions of egg-bearing shrimp in groups ③ and ④. 2) The weight growth rate of group ① was the lowest, the maturation coefficient of unripe shrimp in group ④ was the highest, and the egg-holding rates in groups ③ and ④ were significantly higher than those of group ①. The hatching and survival rates of yellow eggs in group ④ were significantly higher than those in group ②. The hatching and survival rates of red eggs in groups ③ and ④ were significantly higher than those in group ①. (3) The weight gain rate of juveniles in group ④ was significantly higher than those of group ①. (4) Genes and proteins related to ovarian development were screened. In summary, group ④ had a higher proportion of egg-holding shrimp, faster ovarian development, and a higher maturity coefficient. The hatching and survival rates of eggs, and the survival and weight gain rates of the offspring were also high.

Palm oil, with its higher production, lower prices, and higher levels of palmitic acid and oleic acid, may have great potential for use in the aquafeed industry. In this study, with an 8-week feeding experiment, the efficacy of palm oil as a substitute for fish oil in tiger puffer feeds was comprehensively evaluated. The control diets (FO group) contained 8% marine fish oil as the main lipid source, while in the treatment diets, the added marine fish oil was replaced with palm oil at 25%, 50%, 75%, and 100%, respectively, which was named 25PO, 50PO, 75PO, and 100PO, respectively. Juvenile tiger puffers with an initial weight of 15.0 ± 0.04 g were used, with three replicate tanks of 30 juvenile fish tiger puffer for each dietary group. The fish oil replacement by palm oil did not have an adverse effect on fish growth and feeding, but the weight gain decreased by 17.3% in group PO100. Palm oil had no significant effects on fish proximate composition and muscle texture. The effects of dietary palm oil on muscle fatty acid composition were not significant, with DHA and EPA significantly lowered only in the 100PO group. In contrast, the changes in liver and intestinal fatty acid compositions in response to diets were more significant than those in the muscle. In the intestine, the replacement of more than 50% fish oil by palm oil significantly downregulated the gene expression associated with peroxisomal fatty acid β-oxidation and triglyceride hydrolysis, while upregulated the expression of cholesterol biosynthetic genes. In the liver, the replacement of more than 75% fish oil also significantly upregulated the cholesterol synthesis. In conclusion, palm oil can replace 75% of added marine fish oil in tiger puffer diets and does not adversely affect the growth performance, feed utilization, muscle composition, and muscle texture.

In the present study, we investigated the effect of dietary supplementation with the probiotic Bacillus amyloliquefaciens AV5 (OR647358) on the growth, serum and mucus immune responses, metabolomics, and lipid metabolism of Oreochromis niloticus. Fishes (27.2 ± 1.7 g and 9.0 ± 1.2 cm) were fed three distinct meals: a commercial diet (control-GC) and two treatment diets supplemented with probiotics at 10⁶ (G1) and 10⁸ cfu/g (G2), respectively, for 30 days. In the G2 group, the final weight, specific growth rate, weight gain rate, survival rate, and feed conversion ratio of the fish were significantly improved (p < 0.05). Lysozyme, myeloperoxidase, and alkaline phosphatase activities in the mucus of fish were significantly higher (p < 0.05) in the G1 and G2 groups. The serum total protein, superoxide dismutase, glutathione peroxidase, reactive oxygen species, and reactive nitrogen species levels were noticeably higher (p < 0.05) in fish fed G1 and G2. In addition, in the G1 and G2 groups, higher levels of enzymes involved in lipid metabolism, such as pyruvate kinase, 2-hydroxyethyl-ThPP, and dihydrolipoamide dehydrogenase, were increased. Distal gastrointestinal metabolites, such as glycerophospholipids and histidine, were observed. These findings strongly indicate that incorporating B. amyloliquefaciens AV5 at 10⁸ cfu/g into commercial feeds positively influences fish growth, immunity, and lipid metabolism.

Pikeperch (Sander lucioperca) is a species with great potential for aquaculture in Eurasian countries, while feed costs limit the scale of pikeperch farming. Adding carbohydrates to the feed as an energy source is a viable approach to reduce costs and to improve the culture status of pikeperch. In this study, in order to determine the optimal carbohydrate requirement of pikeperch, three tapioca starch (8%, 10%, and 12%) added feeds were produced with isonitrogenous (51%) and isolipidic (11%). For 8 weeks, body weight was 1.20 ± 0.01 g, pikeperch were manually fed the trio of experimental diets until they seemed fully satisfied. The finding revealed that pikeperch can utilize dietary carbohydrate, but excessive dietary carbohydrate will adversely affect the growth performance. The growth and survival rate were decreased in pikeperch in S12 (P < 0.05). The α-amylase activity of S12 reduced in the intestine and lipid deposition was observed in the liver compared with the S8. In addition, proinflammatory cytokines, interleukin 1 beta (il1-β), interleukin 8 (il8), and tumor necrosis factor beta (tnf-β), in the liver and intestine elevate and anti-inflammatory cytokines, interleukin 10 (il10) and transforming growth factor beta (tgf-β), decrease with increasing dietary carbohydrate levels. Hepatic and intestinal antioxidant capacity were also adversely affected, with S12 significantly increasing malondialdehyde (MDA) contents and decreasing glutathione (GSH) and total antioxidant capacity (T-AOC) (P < 0.05). The intestinal barrier function is also damaged, the height and width of intestinal villi decreased, and the expression of occludin-a, occludin-b, and zonula occludens-2 (zo-2) genes was decreased. Elevated levels of starch intake led to harm to gut microflora, reducing bacterial populations, simultaneously boosting the presence of detrimental bacteria (Proteobacteria, Actinobacteriota, Achromobacter, and Rhodococcus) and diminishing the beneficial bacteria (Firmicutes). In conclusion, moderate addition of starch as an energy source can reduce feed costs; however, over addition can bring about organism damage and is recommended to be added at less than 10%.

The razor clam Sinonovacula constricta, a commercially important and nutritionally valuable bivalve species, has been found to display notable responses to different light spectra. While previous research has highlighted the influence of light spectra on the growth, feeding rate, and various physiological characteristics of S. constricta, its impact on the biochemical composition of this species remains unclear. Herein, we investigated the proximate, fatty acid, and amino acid compositions of S. constricta cultured under various light spectra, including white, violet, blue, cyan, green, yellow, red, and darkness. Furthermore, we explored the potential molecular mechanisms underlying these observations through transcriptomic analysis. The results indicate that the light spectrum has a significant impact on the growth, biochemical composition, and gene expression of juvenile S. constricta. Specifically, culturing S. constricta under the yellow light led to improved growth rate (1.09 ± 0.03%/day), higher levels of carbohydrate (26.27% ± 0.49%), crude lipid (11.99% ± 0.23%), energy contents (14,611.34 ± 1,067.01 kJ/kg), and essential amino acids (15.22 ± 0.01 g/kg), as well as increased proportions of polyunsaturated fatty acids (12.38 ± 0.31 µg/mg). These findings suggest that yellow light may play a crucial role in enhancing the nutritional quality of S. constricta. Moreover, the transcriptomic analysis revealed that the yellow light treatment upregulated pathways related to fatty acid biosynthesis, glycine, serine, and threonine metabolism and fatty acid metabolism. This indicates that yellow light may influence nutrient metabolism regulation in S. constricta, potentially leading to the observed changes in biochemical composition. Overall, our study recommends cultivating juvenile S. constricta under yellow light to optimize their growth and nutritional value. Further research could delve deeper into the molecular mechanisms underlying the effects of different light spectra on S. constricta to enhance our understanding of how light influences aquaculture practices and the nutritional quality of seafood products.

This study was conducted to estimate dietary valine (Val) requirement for juvenile olive flounder (Paralichthys olivaceus). In a feeding trial, a total of 540 fish (initial body weight: 23.0 ± 0.2 g) were stocked into 18 tanks (210 L). Six experimental diets containing graded levels of Val (4, 8, 12, 16, 20, and 24 g/kg, dry matter basis) were fed to the fish in triplicate groups for 13 weeks. The lowest growth, feed utilization, and survival were observed in 4 g/kg Val group (P < 0.05). Dietary Val deficiency resulted in significant decreases (P < 0.05) in whole-body protein and Val concentrations, hepatosomatic index, condition factor and plasma protein and cholesterol levels. Nonspecific immunity and antioxidant activities were significantly lower (P < 0.05) in 4 g/kg Val group than in other groups. Dietary Val deficiency upregulated the expression of proinflammatory cytokines and downregulated the expression of anti-inflammatory cytokines and intestinal tight junction protein (occludin) (P < 0.05). Mucosal fold height and submucosa and muscularis thickness of fish intestine were significantly lower (P < 0.05) in fish fed 4 g/kg Val diet. Relatively lower lipid droplet in hepatic cell was observed in 4 g/kg Val group. Our findings suggested that dietary Val requirements for juvenile olive flounder would be 17.7–18.9 g Val/kg (35.4–37.8 g/kg on the basis of crude protein), estimated by quadratic regression analysis based on the weight gain, protein efficiency ratio, and protein retention efficiency.

The objective of this research was to investigate how dietary antimicrobial peptides (AMP), namely, Isalo scorpion cytotoxic peptide (IsCT), affect the gill physical barrier function and immune function of grass carp challenged with Flavobacterium columnare (F. columnare). Five hundred forty grass carp were randomly allocated to six groups and fed to varying levels of IsCT in the diet (0, 0.6, 1.2, 1.8, 2.4, and 3.0 mg/kg diet) for a duration of 60 days. Afterward, the grass carps faced a challenge from F. columnare. The results revealed that the use of optimal IsCT dramatically mitigated gill damage in grass carp that were infected with F. columnare. Additionally, IsCT exhibited a notable enhancement in gill antioxidant capabilities, as evidenced by a significant reduction in ROS, MDA, and PC levels, an elevation in antioxidant enzyme activities, and an upregulation of antioxidant-related genes and Nrf2 mRNA levels. Conversely, the expression of Keap1a and Keap1b mRNA was decreased. Besides, IsCT exhibited its capability to inhibit apoptosis via downregulating the mRNA levels of caspase-2, caspase-3, caspase-7, caspase-8, caspase-9, Apaf1, Fasl, Bax, and JNK while concurrently increasing the mRNA levels of Bcl-2, Mcl-1, and IAP in fish gills. Additionally, IsCT promoted the integrity of tight junction barrier by increasing the gene expression of claudin-b, claudin-c, claudin-3c, ZO-1, ZO-2b, occludin, and JAM while suppressing MLCK signaling. Additionally, optimal dietary IsCT improved antibacterial ability, as evidenced by heightened LZ, ACP activities, and elevated levels of C3, C4, and IgM. Additionally, there was an upregulation in β-defensin-1, LEAP-2A, LEAP-2B, hepcidin, and mucin-2 mRNA expression in the gills. Simultaneously, the inclusion of optimal dietary IsCT in the diet resulted in improved gill immunity barriers through the reduction of proinflammatory cytokine mRNA levels and the increase in the expression of anti-inflammatory cytokine mRNA levels. This was partly facilitated by the IκBa/NF-κB p65 signaling pathway and TOR/S6K1 signaling pathways in the gills of grass carp. Therefore, supplementing the diet with IsCT has potential advantages in enhancing gill health by improved physical barriers and immunity in grass carp. Based on LZ activity and against lipid peroxidation, optimum IsCT concentrations in on-growing grass carp (136.88 ± 0.72 g) were found to be 1.68 and 1.54 mg/kg diet, respectively.

The study of fish larval nutrition is important as dietary requirements change significantly with growth. Vieja zonata is a cichlid species that is endemic to Mexico. In this study, we investigated the ingestion rate, prey selectivity, and growth of V. zonata larvae that were fed on prey cultured with and without probiotics. We conducted three experiments to test the acceptability of the prey offered, determine the optimal density of the prey items, and observe the effect of probiotics on the larvae’s growth. The first experiment tested the acceptability of the prey offered to 5 days post-hatched (dph) V. zonata larvae, and the second experiment determined the optimal density of the prey items. In the third experiment, we individually placed 5 dph larvae (SL = 5.97 ± 0.13 mm; 8.5 ± 0.25 mg) and fed them for 10 days with three different prey items: two rotifer species (Brachionus angularis and Plationus patulus at a density of 20 ind/mL) and a cladoceran species (Moina cf. macrocopa at 1 ind/mL), both cultures with and without probiotics. We counted the prey items consumed daily and provided fresh media with new prey at the above density. We determined the total counts, ingestion rates, and Manly’s selectivity index (α_i) and measured and weighed the larvae at the beginning and end of the experiment. The endogenous feeding period with the yolk sac lasted until 5 dph, a mixed period with endogenous and exogenous feeding occurred from 5 to 7 dph, and an exogenous feeding period in which they fed on zooplankton was observed from day 7 to 15 dph. Brachionus angularis and Plationus patulus were accepted as prey after 5 dph, and Moina cf. macrocopa was accepted on 11 dph. During the first days of feeding, the preferred prey item was P. patulus, which later switched to M. cf. macrocopa on day 11. We found that the use of prey produced with NanoCrusta probiotics resulted in a significant increase in the somatic growth and weight of V. zonata. Our findings suggest that probiotics may potentially enhance the nutritional value of prey items and promote the growth of V. zonata larvae.

This study investigated the effect of adding the compound acidifiers on the intestine health of hybrid grouper (Epinephelus fuscoguttatus ♀ × E. lanceolatus ♂) fed diet with higher cottonseed protein concentrate (CPC). To assess the benefits of compound acidifiers helping CPC to replace more fish meal (FM) for hybrid grouper, five isonitrogen and isolipid experimental diets were formulated. The five diets consisted of a control diet (FM, 50%) and four experimental diets (27.5% FM, 27.27% CPC), each of which contained compound acidifiers to varying degrees (FCA0, FCA0.05, FCA0.1, and FCA0.2). Each diet was fed to three replicates of each group for 8 weeks. In the FCA0.05 group, the results demonstrated a statistically significant increase in protein efficiency ratio, lipid efficiency ratio, and the activity of digestive enzymes in the intestine (P < 0.05). In the FCA0.05 group, there was a clearly enhanced expression of anti-inflammatory cytokines in the intestines (P < 0.05). In the FCA0.1 group, there may be an increase in the expression of important genes involved in fatty acid metabolism in the intestinal (P < 0.05). Appropriate compound acidifiers decreased the relative abundance of Vibrio and other harmful bacteria in the intestine flora that were brought by high CPC. In conclusion, when the hybrid grouper was given a diet containing more CPC, the FCA0.05 group was able to promote intestinal development, enhance digestive enzyme activity and feed consumption, raise antioxidant enzyme activity and anti-inflammatory factor expression, and improve intestinal health.

This study aimed to investigate the effects of replacing inorganic trace minerals (ITM) with organic trace minerals (OTM) on growth performance, body composition, gut histomorphometry, digestive enzyme activity, apparent digestibility coefficients (ADC), and mineral balance in juvenile Nile tilapia, Oreochromis niloticus. Fish (n = 432; 2.5 ± 0.5 g) were randomly distributed into four groups with four replicates each (27 fish per replicate). A control diet (gross 15.2 MJ gross energy kg⁻¹; 367.3 g crude protein kg⁻¹) was elaborated to meet the dietary requirements of zinc (Zn), manganese (Mn), and copper (Cu) using ITM in the sulfate form (ITM100). From the control diet, three diets were elaborated using OTM to supply 100% (OTM100), 75% (OTM75), and 50% (OTM50) of Zn, Mn, and Cu ITM of the control diet, respectively, supplied in the glycinate form. Fish were hand-fed six times daily for 8 weeks. Growth performance was not changed by dietary treatments. Fish fed on the diet OTM50 showed higher whole-body and vertebrae ash contents and higher whole-body calcium (Ca), Zn, and iron (Fe) retention than those fed on the control diet. The activity of digestive enzymes and the ADC of energy and nutrients, including Zn, Mn, and Cu, were similar in fish fed on diets OTM50 and ITM100. A reduction in Zn (−39.8%), Mn (−11.1%), and Cu (−14.0%) loss was observed in fish fed on the diet OTM50 than in fish fed diet ITM100. The dietary treatments did not affect the gut histomorphometry. In conclusion, the inclusion of OTM in Nile tilapia’s diets represents a promising strategy to reduce 50% of ITM sources by utilizing Zn, Mn, and Cu OTM as glycinates without detrimental effects on growth performance, nutrient utilization, and gut function. These results additionally reinforce the environmental benefits of using OTM for precise mineral nutrition in aquaculture.