Inositol Inclusion Affects Growth, Body Composition, Antioxidant Performance, and Lipid Metabolism of Largemouth Bass (Micropterus salmoides).

The present study explored the effects of inositol on growth performance, body composition, antioxidant performance, and lipid metabolism of largemouth bass (Micropterus salmoides). Six isonitrogenous and isolipidic diets containing 0 mg/kg (G1, control), 125 mg/kg (G2), 250 mg/kg (G3), 375 mg/kg (G4), 500 mg/kg (G5), and 625 mg/kg (G6) inositol were prepared and fed to cultured fish (initial weight: 110 ± 1 g) for 8 weeks in recirculating the aquaculture systems. The results indicated that compared with G1 group, the weight gain rate (WGR), specific growth rate (SGR), and feed efficiency rate (FER) in the G3 group were significantly higher. The crude lipid content of the whole fish and the liver of cultured fish was significantly reduced with increasing dietary inositol inclusion. However, no significant effects on moisture, crude protein, and ash contents of fish were observed among the different groups. Dietary inositol supplementation significantly increased muscular crude protein. However, muscular total lipid contents were decreased when the inclusion level was higher than 250 mg/kg (G3-G6 groups). As dietary inositol supplemental level increased, serum triglyceride (TG), and cholesterol (TC) contents showed an increasing trend and reached the maximum value in the G3 group. Additionally, serum low-density lipoprotein cholesterol (LDL-C) in G2, G3, G4, and G5 groups was significantly upregulated by increasing inositol. While, there was no significant change in serum high-density lipoprotein cholesterol (HDL-C) among the treatments. Inositol inclusion also significantly reduced the serum alkaline phosphatase (AKP), glutamic-pyruvic transaminase (ALT), and glutamic-oxaloacetic transaminase (AST) activities as well as serum malondialdehyde (MDA) content but significantly increased serum catalase (CAT), superoxide dismutase (SOD) activities, and total antioxidant capacity (T-AOC). Compared with the control group, the activities of hepatic total lipase (TL) and lipoprotein lipase (LPL) were significantly elevated in the G3, G4, and G5 groups. Above all, dietary inositol supplementation could improve growth performance and antioxidant capacity, and reduce the liver fat content of largemouth bass, and the optimal supplementation level of inositol in feed is estimated to be 250.31-267.27 mg/kg.

Effects of Dietary Folic Acid Supplementation on Sex Differences in Oriental River Prawn, Macrobrachium nipponense.

To better understand the sex differences in the utilization of folic acid for male and female prawns, Macrobrachium nipponense, three experimental diets with graded folic acid contents (A: 1.22 mg/kg, B: 5.44 mg/kg, and C: 10.09 mg/kg) were provided to prawns for 8 weeks. The experimental study demonstrated that prawns fed diets containing 1.22 mg/kg showed the best values on body weight gain (BWG), specific growth rate (SGR), and individual weight for both males and females. Male prawns fed above 1.22 mg/kg of dietary folic acid significantly decreased the crude protein contents in their bodies (p < 0.05), while no significant differences were observed in females among all treatments (p > 0.05). The protease activity of the hepatopancreas in females was significantly (p < 0.05) improved by a dietary level of 10.09 mg/kg of folic acid. However, the opposite trend was observed in males, with the highest protease activity observed at a dietary level of 1.22 mg/kg folic acid. Increasing dietary folic acid levels did not suppress early maturation but led to an increase in the fecundity of females. Furthermore, prawns fed with 10.09 mg/kg of folic acid exhibited improved tolerance against thermal stress in both males and females. Transcriptome analysis revealed that during thermal stress, the "Oxidative phosphorylation" and "Pantothenate and CoA biosynthesis" signaling pathways were significantly enriched in females, and the "Fatty acid biosynthesis" signaling pathway was significantly enriched in males. The results of this study preliminarily evaluate the differences between male and female M. nipponense in response to different dietary folic acid levels and are helpful in promoting the health and growth of aquaculture production of this species.

Effects of Dietary Phaffia rhodozyma Astaxanthin on Growth Performance, Carotenoid Analysis, Biochemical and Immune-Physiological Parameters, Intestinal Microbiota, and Disease Resistance in Penaeus monodon.

The present study aimed to investigate the effect of dietary astaxanthin (Ast) from Phaffia rhodozyma on growth performance, survival, carotenoid content, the activity of antioxidant and immune-related enzymes, intestinal microbiota comparison, and disease resistance against Vibrio parahaemolyticus in Penaeus monodon. Juveniles (average weight 3.15 ± 0.12 g) were fed with six experimental diets supplemented with 0 (Control), 20.5, 41, 61.5, 82, and 102.5 mg/kg of Ast (defined as diet A-D) in triplicate for 56 days. The results indicated that shrimp fed with Ast supplementation significantly (p < 0.05) improved growth performance compared with the control. Furthermore, significantly (p < 0.05) increased survival and decreased feed conversion ratio (FCR) demonstrated the beneficial effects of dietary Ast on enhancing nutrient utilization and ultimately improving the growth and survival of shrimp. Furthermore, shrimp fed with Ast including diet developed a deeper red color than the control, consistent with the significantly (p < 0.05) increased Ast deposition in the shrimp shell. Hemolymph-immunological parameters [aspartate aminotransferase (AST), alanine aminotransferase (ALT), and alkaline phosphatase (AKP)] and hepatopancreatic antioxidant status [total antioxidant capacity (T-AOC), malondialdehyde (MDA), catalase (CAT), and superoxide dismutase (SOD)] were significantly (p < 0.05) affected by dietary Ast supplementation. Dietary increasing Ast levels significantly (p < 0.05) increased shrimp resistance performance to V. parahaemolyticus according to the LT50 results in the current study, which may be caused by increased total carotenoid contents in shrimp tissues from all the Ast-supplemented treatments. Conversely, intestinal microbiota biodiversity and richness were not affected by dietary Ast. The best performances of growth, antioxidant status, immunological response, and carotenoid deposition were observed in diets E and F among all the Ast-supplemented treatments. Overall, all the data suggested that dietary P. rhodozyma Ast played a critical role in improving growth performance, achieving the desired coloration, increasing carotenoid content, and keeping better health status of shrimp. Based on these positive performances, P. rhodozyma Ast could gain the trust of the consumers as a natural source and provide a potential alternative for synthetic Ast using in the Penaeus monodon culture industry.

The effect of dietary supplementation of Astragalus membranaceus and Bupleurum chinense on the growth performance, immune-related enzyme activities and genes expression in white shrimp, Litopenaeus vannamei.

A 56-day feeding trial was conducted to investigate the effects of dietary supplementation of Astragalus membranaceus or/and Bupleurum chinense on the growth performance, immune enzymes, and related gene expression of Pacific white shrimp (Litopenaeus vanammei). Six experimental diets were formulated and supplemented with two levels (0.25% and 0.5%) of each herb and their combination. At the end of the trial, the specific growth rate and feed conversion ratio of shrimp were significantly (P < 0.05) improved by herbal diets. Besides, the activities of immune-related enzymes such as superoxide dismutase (SOD), alkaline phosphatase (AKP), and lysozyme in serum and hepatopancreas were significantly (P < 0.05) elevated in shrimp fed A. membranaceus or/and B. chinense. The high expression levels of immune deficiency (IMD), lysozyme, and Toll-like receptor mRNA directly or indirectly reflected the activation effect of innate immune in shrimp by dietary A. membranaceus or/and B. chinense. However, no significant difference (P > 0.05) among the herbal incorporated treatments was detected on the growth performance and immune response. In conclusion, the results suggest that A. membranaceus and B. chinense could be used as a beneficial feed additives and alternatives to antibiotics for white shrimp aquaculture.

Interactive effects of dietary cholesterol and phospholipids on the growth performance, expression of immune-related genes and resistance against Vibrio alginolyticus in white shrimp (Litopenaeus vannamei).

A 56-day feeding trial was done to investigate the interactive effects of cholesterol (CHO) and phospholipids (PL) on the growth performance, immune response, expression of immune-related genes, and resistance against Vibrio alginolyticus of freshwater cultured white shrimp (Litopenaeus vannamei). A 3 × 3 experimental design was conducted with nine experimental diets containing three levels of CHO (0, 0.2%, and 0.4%) and three levels of PL (0, 2%, and 4%). The results indicated that the growth performance significantly (P < 0.05) increased with the increase in dietary CHO levels. Interactive effects between dietary CHO and PL on the growth parameters were not observed. Superoxide dismutase (SOD) and lysozyme activities were also significantly affected by dietary CHO levels. Furthermore, the interaction between these two additives was only detected in SOD activity. Shrimp fed experimental diet with CHO and PL supplementation showed better tolerance against Vibrio alginolyticus compared to the control, interactive effects (P < 0.05) were also detected on these two factors. The expression of immune deficiency (IMD) and lysozyme mRNA was up-regulated in shrimp fed diets with CHO and PL. The expression level of Toll-like receptor mRNA directly reflected the dietary CHO levels, which was not affected by dietary PL. The interaction between dietary CHO and PL was shown as the significant factor (P < 0.05) both in the expression of IMD and lysozyme mRNA, which indicated that different dietary levels of CHO and PL could strongly affect expression levels of some immune-relevant genes of the juvenile freshwater cultured L. vannamei.

Impact of dietary oil replacement on muscle and liver enzymes activity, histomorphology and growth-related genes on Nile tilapia.

This study evaluated the efficacy of replacing dietary fish oil (FO) with vegetable oils (virgin coconut and corn oil) on enzyme activities (glycolytic, oxidative and lipid metabolites), mRNA expression of lipid metabolic genes and histomorphology of liver and intestine in O. niloticus. O. niloticus (6.07 ±â€¯0.07 g) was fed six experimental diets where fish oil (FO) served as the control diet, and then was supplemented by dietary oils; virgin coconut oil (VCO) {3%FO + 3%VCO; 3FVCO}, and corn oil (CO) {3%FO + 3%CO; 3FCO}, 6%VCO (VCO), 6%CO (CO) and 6%VO {3%VCO + 3%CO; VO}. Growth performances measured indicated fish fed diet 3FCO had higher weight gain (WG) and specific growth rate (SGR). Fish fed diet 3FCO recorded the highest activities in lactate dehydrogenase (LDH), pyruvate kinase (PK), citrate synthase (CS), cytochrome coxidase (COX), malic enzymes (ME) and lipoprotein lipase (LPL) respectively. Stearoyl-CoA desaturase (SCD1) was upregulated in groups fed diets 3FVCO and 3FCO. Also, groups fed diet VCO and CO expressed highly in LPL, whereas, elongase of very long-chain fatty acids (ELOVL-5) was not influenced by the lipid sources. Histological representations in the liver were highly impacted in vegetable diets where lipid accumulation was higher except those fed VCO. However, in the digestive tract from distal to middle and posterior, the same group (VCO) exhibited altered morphological structure as those fed diet 3FCO were similar to FO. The study shows that, corn oil in diets relates positively to growth and enzymatic activities which becomes evident in their depositions in liver and functional intestinal tracts. This study indicates dietary alternatives may cause alterations in lipid metabolic pathways (LPL and SCD1) involved in fatty acid transport. As such, polyunsaturated fatty acid (PUFA) rich diets (CO) based on this study results increases metabolic activities involving especially the production, distribution and consumption of adenosine triphosphate (ATP) in O. niloticus.

Long-duration effect of multi-factor stresses on the cellular biochemistry, oil-yielding performance and morphology of Nannochloropsis oculata.

Microalga Nannochloropsis oculata is a promising alternative feedstock for biodiesel. Elevating its oil-yielding capacity is conducive to cost-saving biodiesel production. However, the regulatory processes of multi-factor collaborative stresses (MFCS) on the oil-yielding performance of N. oculata are unclear. The duration effects of MFCS (high irradiation, nitrogen deficiency and elevated iron supplementation) on N. oculata were investigated in an 18-d batch culture. Despite the reduction in cell division, the biomass concentration increased, resulting from the large accumulation of the carbon/energy-reservoir. However, different storage forms were found in different cellular storage compounds, and both the protein content and pigment composition swiftly and drastically changed. The analysis of four biodiesel properties using pertinent empirical equations indicated their progressive effective improvement in lipid classes and fatty acid composition. The variation curve of neutral lipid productivity was monitored with fluorescent Nile red and was closely correlated to the results from conventional methods. In addition, a series of changes in the organelles (e.g., chloroplast, lipid body and vacuole) and cell shape, dependent on the stress duration, were observed by TEM and LSCM. These changes presumably played an important role in the acclimation of N. oculata to MFCS and accordingly improved its oil-yielding performance.

Orthogonal test design for optimization of lipid accumulation and lipid property in Nannochloropsis oculata for biodiesel production.

In order to improve the property of Nannochloropsis oculata as biodiesel feedstock, a L9(3(4)) orthogonal test on limited nitrogen supplementation (0, 0.22 and 0.44 mmol N L(-1)), high iron concentration (1.2×10(-2), 1.2×10(-1) and 1.2 mmol Fe L(-1)) and culture temperature (10, 20 and 30 °C) was conducted to select the most effective combinational measurement. Results showed that microalgae displayed the highest total lipid content (60.44±0.68%), the highest neutral lipid proportion (90.74±0.18%), the highest lipid yield (152.70±7.40 mg L(-1)) and the largest cetane number (CN, 64.34±0.13) under different combined conditions. There were significant interaction among nitrogen supplementation, iron concentration and culture temperature on the lipid yield and CN of N. oculata. Nitrogen supplementation, followed by iron concentration and temperature orderly, was the most influential factor in lipid yield. It is therefore suggested that the combination of 0.44 mmol N L(-1), 1.2×10(-1) mmol Fe L(-1) and 20 °C was the best measurement for improving the property of N. oculata as biodiesel feedstock.

The effect of Sargassum fusiforme polysaccharide extracts on vibriosis resistance and immune activity of the shrimp, Fenneropenaeus chinensis.

Immunostimulants are valuable for control of shrimp diseases and the immunostimulatory effects of some polysaccharide additives for shrimp have been reported. In this study, the Sargassum fusiforme polysaccharide extract (SFPSE) was assessed as a feed additive when supplemented in the diet (0%, 0.5%, 1.0%, and 2.0%) for juvenile shrimp, Fenneropenaeus chinensis, in order to study the effects of SFPSE on vibriosis resistance and immune activity. Shrimp were cultured in the same pond with cages. The body weight, survival, the cumulative mortality after injection with Vibrio harveyi (30 microl V. harveyi suspension at 9.3 x 10(7) CFU ml(-1) per shrimp), the total haemocyte counts (THCs), the protein concentration and the phenoloxidase (PO) activity in supernatant of haemolymph, the lysozyme (LSZ) and superoxide dismutase (SOD) activity in muscle of the shrimp were assayed after 14 days feeding period. The results indicated that shrimp survival under the stress of V. harveyi was affected by the dietary SFPSE. The shrimp treated with 1.0% and 0.5% SFPSE displayed significantly lower cumulative mortalities after being injected with V. harveyi suspension 24 and 30 h later, respectively, compared with that of the control. However, cumulative mortality of 2.0% SFPSE treatment was not significantly different from that of the control. There was no significant difference of cumulative mortality between 0.5% and 1.0% SFPSE treatment groups. The immune activities of the shrimp also were affected by dosage of dietary SFPSE. The THCs of the shrimp rose with increasing SFPSE dosage. The protein concentration and PO activity in supernatant of haemolymph as well as muscular LSZ activity first rose then dropped with increasing SFPSE dosage. The protein concentration in supernatant of haemolymph appeared a maximum of 167.46 mg ml(-1) in 1.0% SFPSE treatment. The PO activity and LSZ activity reached the peaks as 13.20 U and 3.21 U mgprot(-1) in 0.5% SFPSE treatment, respectively. SOD activity of the shrimp was not significantly affected by dietary SFPSE. It is therefore suggested that oral administration of SFPSE at an optimal level of 0.5% and 1.0% for 14 days effectively improved vibriosis resistance and enhanced immune activity of the shrimp in general.