Immune gene expression and antioxidant response to vitamin E enriched diets for males Litopenaeus vannamei breeder (Boone, 1931).

The is aim of this study was to evaluate if vitamin E supplementation to diet could improve the spermatic quantity and quality in males of Litopenaeus vannamei. A basal diet with 171.5 mg/kg (included in commercial vitamin premix) and experimental diets with 3 concentrations of vitamin E: 620 (diet A), 1069 (diet B) and 1517 (diet C) mg/kg were tested by 30 days. 500 L tanks were set up for each treatment, and seven males were set in each tank. Circulant cholesterol, triglyceride (TG), glucose, total protein was measured. Sperm quantity and quality were classified as normal, abnormal, or dead. In reproductive tract was measured the activity and differential expression lipid soluble antioxidant system (LSAS) and of immune genes system. The higher sperm quantity was obtained in A diet and decreased in shrimp fed B and C diets (p < 0.05). Males fed diets B and C presented a higher activity and relative expression of lipid system oy suggesting oxidative stress. A significant increment of prophenol oxidase (proFo) and α-2-macroglobulin (α-2 M) transcripts were observed in males fed C diet (p < 0.05). All these variables were present in males with low sperm amount and low hemocyanin gene expression (p < 0.05). Therefore, diet A supplemented with 620 mg/kg vitamin E could benefit males L. vannamei broodstock, taking a count the sperm quantity and all the lipid and immune genes response.

Nutritive value of diets containing fish silage for juvenile Litopenaeus vannamei (Bonne, 1931).

BACKGROUND: Fish wastes has been used for many years as an alternative in feeds for aquaculture. In the present study weight gain of juvenile white shrimp Litopenaeus vannamei fed diets including fish waste silage (WS), fish waste silage with soybean meal SBM (WS + S) or fish waste meal (WM) was compared. A conventional acidic silage process was applied to obtain from wastes (skin, heads, bones and viscera) of snapper (Lutjanus spp.), grunt (Haemulon plumieri), and grouper (Epinephelus spp.) an ingredient rich in protein. RESULTS: After 3 days ensilage more than 90% protein was hydrolysed. Waste material processed at pH 3.8 lost about 24% tryptophan. Butylated hydroxytoluene (BHT) prevented lipid oxidation, as shown after 45 days with malonaldehyde production. Shrimp fed WS + S diet gained 0.7 g per week higher than those fed WS and WM diets with 0.3 g per week (P < 0.05). CONCLUSION: WS processed with formic acid under conditions of low pH is beneficial for the white shrimp L. vannamei. It sustained reasonable weight gain combined with soybean meal in practical diets. On the other hand, BHT addition was beneficial in preventing oxidative action during silage preparation.

Partial substitution of frozen-fresh food by an experimental diet in Litopenaeus vannamei (Boone, 1931) (Decapoda: Dendrobranchiata: Penaeidae) broodstock.

The aim of this study was to determine the effect of completely or partially replacing fresh foods from the broodstock diet with an experimental diet. During a 40-day period, three dietary treatments were tested on Litopeaneus vannamei broodstock. As part of the first dietary treatment, denoted as "FF", broodstock shrimp were fed only fresh frozen food (squid, polychaete, mussel and Artemia biomass). The second treatment denoted as "ED" was 100% an artificial experimental diet. The third treatment, denoted as MD, comprised both the experimental diet and the fresh-frozen food (only squid and mussel were used). In terms of fertile spawns, females with ≥ 1 spawn, females with ≥ 2 spawn, and fecundity, the MD treatment did not differ significantly from the FF treatment. Fecundity was lowest among females receiving the ED treatment. MD treatment demonstrated equivalent fertility in females, and sperm rate in males to that of the FF treatment. The highest normal sperm rate was found in the ED and MD treatments. As a result, a combination of fresh food and the experimental diet resulted in a more balanced reproduction performance.

Effects of using the biofloc system and eyestalk ablation on reproductive performance and egg quality of Litopenaeus vannamei (Boone, 1931) (Decapoda: Dendrobranchiata: Penaeidae).

The aim of this study was to evaluate egg production and quality of females of the Pacific white shrimp, Litopenaeus vannamei, in which there was or was not unilateral eyestalk ablation after there was pre-maturation culturing in biofloc or clear-water systems. Acylglycerides, cholesterol, glucose and total soluble protein were determined for the hepatopancreas, ovaries, hemolymph and eggs. Females cultured using the biofloc system had a larger number of eggs released per spawning and per gram of spawning specimen body weight. The number of total spawning's per week was comparable among treatments. Females cultured in the biofloc system in which there was no eyestalk ablation had that greatest concentrations of nutrient reserves in the hepatopancreas (P < 0.05) with the females cultured in the biofloc and clear-water system that had eye stalk ablation having the next most abundant nutrient reserves. There were the least concentrations of nutrient reserves in females with eyestalk ablation cultured in the clear-water system (P < 0.05). There, however, were no difference in nutrient reserve concentrations in the hemolymph and ovaries. In the eggs, there was the same trend among treatments as the hepatopancreas nutrient reserves, indicating that both eyestalk ablation and pre-maturation culture conditions (i.e., either biofloc or clear-water) affected the quality of eggs in L. vannamei.

Factorial effects of salinity, dietary carbohydrate and moult cycle on digestive carbohydrases and hexokinases in Litopenaeus vannamei (Boone, 1931).

Litopenaeus vannamei were reared in close cycle over seven generations and tested for their capacity to digest starch and to metabolise glucose at different stages of the moulting cycle. After acclimation with 42.3% of carbohydrates (HCBH) or 2.3% carbohydrates (LCBH) diets and at high salinity (40 g kg(-1)) or low salinity (15 g kg(-1)), shrimp were sampled and hepatopancreas (HP) were stored. Total soluble protein in HP was affected by the interaction between salinity and moult stages (p<0.05). Specific activity of alpha-amylase ranged from 44 to 241 U mg protein(-1) and a significant interaction between salinity and moult stages was observed (p<0.05), resulting in highest values at stage C for low salinity (mean value 196.4 U mg protein(-1)), and at D0 in high salinity (mean value 175.7 U mg protein(-1)). Specific activity of alpha-glucosidase ranged between 0.09 and 0.63 U mg protein(-1), an interaction between dietary CBH and salinity was observed for the alpha-glucosidase (p<0.05) and highest mean value was found in low salinity-LCBH diet treatment (0.329 U mg protein(-1)). Hexokinase specific activity (range 9-113 mU mg protein(-1)) showed no significant differences when measured at 5 mM glucose (p>0.05). Total hexokinase specific activity (range 17-215 mU mg protein(-1)) showed a significant interaction between dietary CBH and salinity (p<0.05) with highest value (mean value 78.5 mU mg protein(-1)) found in HCBH-high salinity treatment, whereas in the other treatments the activity was not significantly different (mean value 35.93 mU mg protein(-1)). A synergistic effect of dietary CBH, salinity and moult stages over hexokinase IV-like specific activity was also observed (p<0.05). As result of this interaction, the highest value (135.5+/-81 mU mg protein(-1)) was observed in HCBH, high salinity at D0 moult stage. Digestive enzymes activity is enhanced in the presence of high starch diet (HCBH) and hexokinase can be induced at certain moulting stages under the influence of blood glucose level. Perspectives are opened to add more carbohydrates in a growing diet, exemplifying the potential approach for less-polluting feed.