Crude Lipid Research Articles

Type of black soldier fly (Hermetia illucens) larvae frass influences the nutritional value when included in a prepared diet for Mozambique tilapia (Oreochromis mossambicus)

Black soldier fly (Hermetia illucens) larvae (BSFL) farming is expected to increase, and a by-product is the ‘frass’. The dietary inclusion of BSFL frass has been shown to enhance tilapia and catfish growth/immunity. However, the composition of BSFL frass, and potentially their nutritive value to fish, may depend on the initial provided substrate. In this 8-week nutrition trial, BSFL frass made from either expired fish diet (EFD; 45% crude protein) or a combination of fruits/vegetable peels (FV; 9.3% crude protein) were included in the diets of Mozambique tilapia (Oreochromis mozambicus) at 5% or 10%. The EFD and FV frass had a different nitrogen, mineral, and amino acid profile, and this information was used to formulate the diets. Results showed that EFD frass at 10% significantly (P < 0.05) enhanced tilapia growth compared to fish fed the control diet, but performance of fish fed the other test diets were not different (P > 0.05) from the control. There was no significant difference in the crude protein or lipid content of tilapia, but some differences were observed in the amino acid and fatty acid composition. Among the test minerals, only phosphorus was significantly affected, which was higher in tilapia fed the FV frass diets. Liver histology showed some minor inflammation and blood vessel congestion in tilapia fed the 10% frass diets, while the intestinal histology had a better cumulative score among all the frass diets compared to the control. Results indicate that the initial substrate provided to the BSFL can influence the nutritive value of the frass to fish.

Comparison of Growth Performance, Nutritional Composition, and Muscle Transcriptome between Two Cultured Varieties of the Chinese Mitten Crab (Eriocheir sinensis)

This study evaluated the disparities in growth performance and nutritional composition between two common Chinese mitten crab varieties, “Jianghai 21” and “Changjiang 2”, cultured in Jiangxi Province. Over the breeding period, parameters such as body weight, height, carapace length and width, and lengths of the second and third legs exhibited increases. Growth indices of “Jianghai 21” surpassed those of “Changjiang 2” during the intermediate and late breeding phases. While “Changjiang 2” demonstrated significantly higher crude lipid content than “Jianghai 21”, the latter exhibited markedly higher levels of total amino acids (TAAs), essential amino acids (EAAs), and delectable amino acids. Although overall nutrient composition did not significantly differ, TAA and EAA contents in the hepatopancreas were notably greater in “Jianghai 21” than in “Changjiang 2”. Moreover, a total of 901 differentially expressed genes (DEGs) were identified between the two varieties, with 560 upregulated and 341 downregulated. These DEGs were primarily associated with pathways related to fatty acid degradation, metabolism, and growth regulation. The observed variances in growth performance and nutrient composition between “Jianghai 21” and “Changjiang 2” suggest potential regulation by relevant genes. In summary, the results showed that the growth performance of “Jianghai 21” is greater than that of “Changjiang 2”, offering valuable insights for the selection of aquaculture varieties in the region.

Effect of soybean meal replacement with corn gluten meal on the survival, biochemical and metabolic responses, and disease resistance of Pacific white shrimp (Litopenaeus vannamei)

Abstract This study delves into the potential of replacing soybean meal (SBM) with corn gluten meal (CGM) in the diet of Litopaeneaus vannamei. We aimed to investigate the effects of a dietary soybean meal replacement on various aspects of shrimp, including survival, biochemical indices, digestive enzymes, metabolomics, and disease resistance against Vibrio harveyi. To conduct the study, we fed 840 juvenile Pacific shrimp seven different diets, each containing varying levels of CGM. The control group received a diet with 0% CGM; the other diets contained 3%, 5%, 7%, 9%, 12%, and 14% CGM. Each group comprised three replicates, and the shrimp were fed their diets for eight weeks. Our findings revealed that the survival rate of the shrimp ranged from 90.83% to 97.50% and did not differ significantly between the control and those fed diet treatments 2–5. Additionally, there were no significant differences in crude protein, moisture, and lipid content. However, we observed that total antioxidant capacity content increased with the dietary inclusion of CGM. Furthermore, malondialdehyde content decreased with increasing CGM levels, while superoxide dismutase increased, indicating no obvious oxidative damage was observed in CGM treatment groups. Interestingly, shrimp fed diets 2 and 3 had considerably lower alanine aminotransferase activity than shrimp in the control group. The disease resistance in shrimp was improved across all treatment groups, with a notably higher CGM inclusion having the highest level of mortality during the challenge test. Finally, we analyzed the metabolomics data and found PCA score plots clearly separated the control group and shrimp fed CGM diets. Our study revealed that a 3% substitution rate of SBM with CGM can enhance survival and immunity, regulate metabolites and improve disease resistance.

Enhancement of Growth Performance and Body Coloration Through The Inclusion of Torch Ginger Powder in The Feed of Red Tilapia (Oreochromis sp.)

Red tilapia (Oreochromis sp.) is a highly produced aquaculture fish among freshwater species. Coloration is an important factor in determining consumer preferences. Therefore, an 8-week experiment was conducted to enhance the growth performance and body coloration through the inclusion of torch ginger in the feed of red tilapia. Five experimental feeds were prepared from commercial feed (crude protein: 34%, crude lipid: 5%) containing torch ginger powder at 2.5, 5.0, 7.5, and 10% (T1, T2, T3, &amp; T4) inclusion levels while feeding without torch ginger act as a control (T0). Red tilapia (Initial body weight: 0.4±0.1g; Initial total length: 4.0±0.1cm) were distributed at stocking number 20 fish/tank into fiberglass tanks with a capacity of 80 L and triplicates for each treatment. The fish were fed with experimental feeds until satiation. The growth of fish was significantly higher (P&lt;0.05) when the fish fed with T1, T2, and T3 compared to control treatment T0. Moreover, the feed intake was significantly increased (P&lt;0.05) when the torch ginger powder was added to the experimental feeds. In addition, the FCR was significantly better (P&lt;0.05) when the fish fed on T1, T2, and T3 compared to T0. The inclusion of torch ginger powder in the feed did not significantly affect (P&lt;0.05) the body protein and lipids of the experimental fish. The increment of redness was significantly higher (P&lt;0.05) when the fish fed with T1, T2, T3, and T4 compared to T0. However, it showed a declining trend of redness when the inclusion of torch ginger increased to 5.0% and above. Thus, the present study suggested that the inclusion of torch ginger powder improved the performance and enhanced the body coloration of juvenile red tilapia. However, a further increase of torch ginger powder by more than 2.5% did not help in the enhancement of the body coloration.

Effects of Dietary Fish Meal Replaced by Cottonseed Protein Concentrate on Growth Performance, Antioxidant Capacity, and Liver and Intestinal Health of Juvenile Hybrid Culter

The objective of this study was to assess the impact of concentrated cottonseed protein (CPC) as a substitute for fishmeal (FM) in juvenile hybrid culter (Erythroculter ilishaeformis ♀ × Ancherythroculter nigrocauda ♂). A total of 360 fish with an initial body weight of 10.0 ± 0.5 g were randomly allocated into 12 indoor culture tanks, with each tank containing 30 fish. Four diets were formulated in which fish meal (FM) was replaced by CPC at different inclusion levels: 0% (T0), 15% (T15), 30% (T30), and 45% (T45). The corresponding amounts of CPC included were 0, 61, 122, and 182 g/kg, respectively. At the end of the 10-week feeding trial, the findings revealed an inverse correlation between the proportion of CPC replacing FM and both final body weight (FBW) and weight growth rate (WG) in hybrid culter. Specifically, the T30 and T45 groups exhibited significantly lower FBW and WG compared to the T0 group (p &lt; 0.05). No significant differences in crude protein and ash contents were observed among all groups (p &gt; 0.05). However, the crude lipid content was highest in hybrid culter fed the T45 diet and lowest in the T0 group (p &lt; 0.05). There were no significant differences in muscle amino acid composition among all treatment groups (p &gt; 0.05). The contents of total protein (TP) and albumin (ALB) declined slightly as the proportion of FM substituted by CPC increased, yet this decline did not reach statistical significance (p &gt; 0.05). Serum alanine aminotransferase (ALT) activity elevated with increasing dietary CPC, and the T45 group exhibited significantly higher ALT activity compared to the T0 group (p &lt; 0.05). The hepatic activities of superoxide dismutase (SOD) and catalase (CAT) were significantly lower in the T45 group than in the T0 and T15 groups (p &lt; 0.05). Furthermore, there was a decrease in intestinal villi length with an increasing replacement ratio of FM by CPC, and the villi length in the T45 group exhibited a significant reduction when compared to that in the T0 group (p &lt; 0.05). It is concluded that replacing 15% FM with CPC does not exert obviously detrimental effects on growth performance, serum biochemical indices, intestinal morphology, muscle amino acid profile, or antioxidant performance of juvenile hybrid culter.

Hermetia illucens Larvae Meal as Partial Fishmeal Replacement in Jade Perch Diet Cultured in Biofloc: Growth Performance, Feed Efficiency and Consumer Acceptance

A 12-week feeding trial on jade perch (Scortum barcoo) was conducted to evaluate the outcomes of partial substitution of fishmeal with black soldier fly larvae meal (BSFLM) in a biofloc system that requires minimal water exchange. The jade perch juveniles were subjected to three dietary treatments namely the 100% fishmeal (FM100), 50% BSFLM (BSF50), and a commercial diet (COM) with 20 individuals per treatment in triplicate tanks. Growth, feed efficiency, and body indices were measured throughout the feeding trial. There were no significant differences observed between the treatments in growth indicators such as the body weight gain (84.55 - 89.10 g), feed conversion ratio (1.77 - 1.87), specific growth rate (1.71 - 1.81 %/day), protein efficiency ratio (1.69 - 1.77), survival rate (90.00 - 98.48 %) and fillet yield (34.94 - 37.08 %). The condition factor is similar in all treatment groups ranging from 1.97 - 2.05. The crude protein and moisture content making up fish body composition are not statistically different among treatments, but higher crude lipids are obtained in the BSF50 (32.33 ± 5.27 g/kg) and COM (31.67 ± 2.76 g/kg). Higher hepatosomatic index (HSI) and visceral fat somatic index (VFSI) values were observed in BSF50 group at 3.13 ± 0.25 and 10.89 ± 1.68, respectively. Furthermore, sensory evaluation comparing the consumers' evaluation and acceptance of the fish cultured with the different dietary treatment and culture system shows that the group fed BSF50 and cultured in biofloc system received similar overall appreciation with the FM100 and COM group. In conclusion, BSFLM inclusion in the jade perch diet, combined with the biofloc system, is feasible to be explored further.

Inhibitory Effect of Prickly Ash (Zanthoxylum bungeanum) Seed Kernel Oil on Lipid Metabolism of Grass Carp (Ctenopharyngodon idellus) in High-Fat Diet

To investigate the effect of prickly ash (Zanthoxylum bungeanum) seed kernel oil (PASO) on the lipid metabolism of grass carp (Ctenopharyngodon idellus) under a high-fat diet, PASO were added into two lipid-level (4 g/kg and 8 g/kg) diets to form four isonitrogenous diets: soybean oil (SO), PASO, high-fat soybean oil (HSO), and high-fat prickly ash seed oil (HPASO). A total of 216 healthy grass carp (9.43 ± 0.82 g) were randomly divided into four groups and fed with the four diets, respectively, for 56 days. The result showed that the viscerosomatic index (VSI) and the content of the crude lipid in the hepatopancreas and muscle was significantly higher by oil levels (p &lt; 0.05). The linolenic acid content in the body of the fish significantly increased in PASO and HPASO compared to that in SO and HSO (p &lt; 0.05). The fatty acid composition of the hepatopancreas, intraperitoneal fat, and muscle in four dietary groups was significantly similar to the fatty acid composition in the diets (p &lt; 0.05). More significant fat infiltration and nuclear translocation in the hepatopancreas of fish was found in the HSO group but was decreased in the HPASO group. The adipocyte size in the intraperitoneal fat tissue in the PASO group was significantly lower than that in the SO group (p &lt; 0.05). The relative mRNA expression of the lipogenesis-related genes ppar-γ, cebp-α, and srebp-1c was significantly down-regulated in the PASO group compared with the SO group (p &lt; 0.05), and the mRNA expression of lipolysis-related genes ppar-α and cpt-1 were significantly up-regulated in the PASO group (p &lt; 0.05). In conclusion, dietary PASO showed the function of reducing lipid accumulation in the fish. This reduction might be attributed to the inhibition of the lipogenesis-related genes and the stimulation of the lipolysis-related genes, which were probably modulated by the high content of linolenic acid in PASO.

Effects of exercise training on the external morphology, growth performance, swimming ability, body composition and metabolism of juvenile black seabream Acanthopagrus schlegelii

Multiple studies have shown that exposure to moderate water currents (exercise training) can improve growth and physiological performance of hatchery-reared fish. Proactive implementation of sustained aerobic swimming training can be particularly beneficial for improving post-release performance of fish in stock enhancement- or ‘ranching’ programs. Black seabream Acanthopagrus schlegelii is an important species in aquaculture and stock enhancement in the East China Sea. For juveniles of this species, we assess the impacts of exercise training at various flow rates on the morphology, growth performance, swimming ability, body composition and locomotors metabolism. A group of sibling juvenile fish (initial mass: 13.72 ± 0.29 g) underwent daily exercise training for 12 h (9:00–21:00) over 30 days at four different water velocities (0, 1, 2, or 4 body lengths per second, BL/s). All the trained fish exhibited a significant decrease in their respiratory metabolic rate during the test of swimming ability. Fish from the 2 BL/s training group exhibited a significantly increased burst swimming speed compared to the other groups. Fish from 1 BL/s training group showed elevated hexokinase activities in the white muscle and citrate synthase activities in the liver compared to the 0 BL/s group. Citrate synthase activities in the white muscle of fish from the 2 BL/s training group were elevated, along with citrate synthase activities in the liver, as compared to 0 BL/s. The fish in the 4 BL/s training group showed a tendency for increased crude protein content and a corresponding decrease in crude lipid content. Morphological analysis revealed that fish in the 4 BL/s group exhibited larger dorsal fins and more streamlined body profiles, compared to 0 BL/s. Activities of white muscle citrate synthase as well as liver hexokinase activity were higher in the 4 BL/s group, while lactate content activity in the white muscle were lower compared to 0 BL/s. These findings underscore the effectiveness of training at 2 BL/s, offering a promising strategy to enhance the performance of juvenile black seabream for stocking initiatives.

Effects of Farming Conditions on the Nutritional Contents of Manihot esculenta Planted in four Regions of Niger Delta, Nigeria

All through human existence, the ability to cultivate crops to better human life has been affected by the nature of the soil; different crops strive in different regions. The relationship between humans, the earth and food production affirms soil as the foundation of crop production. Hence, the objective of this paper as to the effects of farming conditions on the nutritional contents of Manihot esculenta planted in four regions of Niger Delta, Nigeria. Using appropriate standard methods. Data obtained revealed that the moisture contents varied in the order; herbicide &gt; oil-spilled &gt; inorganic fertilizer &gt; normal. The amount of water-soluble vitamins varied in the order; normal &gt; oil spilled &gt; inorganic fertilizer &gt; herbicide. The amount of crude lipids varied in the order; herbicide &gt; normal &gt; inorganic fertilizer &gt; oil-spilled. The amount of hydrogen cyanide varied in the order; inorganic fertilizer &gt; herbicide &gt; oil-spilled &gt; normal. The amount of carbohydrate varied in the order; inorganic fertilizer &gt; oil-spilled &gt; normal &gt; herbicide. The amount of crude protein and fiber varied in the order; herbicide &gt; normal &gt; inorganic fertilizer &gt; oil-spilled. Root tubers from the normal practice was most abundant in ash contents, while that from the use of herbicide was the least. These results indicated that the normal practice showed commended amount of moisture content, water soluble vitamins and ash content; the herbicide induced land produced cassava tuber with the highest amount of crude lipids, crude fibre and crude proteins; that with the use of inorganic fertilizer produced the highest amount of hydrogen cyanide. All practices were adoptive for carbohydrate formation, except the herbicide induced soil.

Effects of Inulin and Mannan-oligosaccharide on growth, feed utilization, fatty acid profiles, and intestinal morphology of Chamo strain Nile tilapia (Oreochromis niloticus) fry reared under suboptimal temperature

The effects of inulin and mannan-oligosaccharide (MOS) on growth, feed utilization, fatty acid profiles, and intestinal morphology of Chamo strain Nile tilapia (Oreochromis niloticus) fry reared at suboptimal temperature were investigated in this study. Chamo strain Nile tilapia is a local strain in Ethiopia that has been selected for fast growth and disease resistance under tropical conditions. However, its performance under cold stress or sub-optimal temperature is unknown. Four experimental diets were formulated to contain 0% (control), 5 g kg-1 inulin, 6 g kg-1MOS and a combination of 2.5 g kg-1 inulin and 3 g kg-1 MOS. Each diet was fed to triplicate groups of Nile tilapia fry (initial weight 1.6 ± 0.074 g) for nine weeks at a suboptimal temperature of 22.88 ± 0.48 oC. The results showed that prebiotic supplementation did not significantly affect the survival, final weight, weight gain, SGR, FCR and ash content of the fish except for the slight improvements observed with MOS alone and in combination with inulin. However, MOS alone or a combination with inulin improved the villi length and width, and some PUFA levels of the fish compared to the control group. The fish fed with the combination of inulin and MOS had the highest crude lipid content and villi length in the proximal and middle intestine among all groups. The fish fed with MOS alone had the highest villi width and some PUFA levels among all groups. These results suggest additions of these prebiotics have improved the villi length and width, and some PUFA levels of Chamo strain Nile tilapia and could be used as sustainable additive in tilapia nutrition under suboptimal temperature conditions Therefore; further studies are needed to optimize the prebiotic supplementation for Nile tilapia under different conditions.

Improvement in Muscle Fatty Acid Bioavailability and Volatile Flavor in Tilapia by Dietary α-Linolenic Acid Nutrition Strategy.

To investigate the modification of muscle quality of farmed tilapia through dietary fatty acid strategies, two diets were formulated. Diet SO, using soybean oil as the lipid source, and diet BO, using blended soybean and linseed oils, each including 0.58% and 1.35% α-linolenic acid (ALA), respectively, were formulated to feed juvenile tilapia for 10 weeks. The muscular nutrition composition, positional distribution of fatty acid in triglycerides (TAGs) and phospholipids (PLs), volatile flavor, lipid mobilization and oxidation were then analyzed. The results showed that there was no distinct difference between the SO and BO groups in terms of the nutrition composition, including crude protein, crude lipid, TAGs, PLs, and amino acid. Although the fatty acid distribution characteristics in ATGs and PLs showed a similar trend in the two groups, a higher level of n-3 PUFA (polyunsaturated fatty acid) and n-3 LC-PUFA (long-chain polyunsaturated fatty acid) bound to the glycerol backbone of TAGs and PLs was detected in the BO group than the SO group, whereas the opposite was true for n-6 PUFA. Additionally, the muscular volatile aldehyde and alcohol levels were higher in the BO group. Moreover, the expression of enzymatic genes and protein activities related to lipid mobilization (LPL, LPCAT, DGAT) and oxidation (LOX and GPX) was higher in the BO group. The results demonstrate that high-ALA diets may improve the fatty acid bioavailability and volatile flavor of tilapia by improving the lipid mobilization and oxidation, which provides new ideas for the improvement of muscle quality in farmed fish.

Marine Fish Oil Replacement with Lard or Basa Fish (Pangasius bocourti) Offal Oil in the Diet of Tiger Puffer (Takifugu rubripes): Effects on Growth Performance, Body Composition, and Flesh Quality.

Lard (LD) and Basa fish offal oil (BFO) have similar fatty acid profiles, both containing high contents of saturated fatty acids (SFA) and monounsaturated fatty acids (MUFA). The present study aimed to investigate the efficacy of partial or complete replacement of marine fish oil (MFO, herring oil) by LD or BFO in the diets of tiger puffer. The control diet contained 49.1% crude protein and 9.28% crude lipid content including 6% added MFO. In other diets, 1/3, 2/3, and 3/3 of the added MFO was replaced by LD or BFO, respectively. Each diet was fed to triplicate tanks of juvenile fish (initial body weight, 13.88 g). A 46-day feeding trial was conducted in a flow-through seawater system. Each diet was fed to triplicate 200-L rectangular polyethylene tanks, each of which was stocked with 30 fish. Fish were fed to satiation three times a day. The complete replacement of added MFO (replacing 65% of the total crude lipid) had no adverse effects on fish growth performance in terms of survival (>94%), weight gain (360-398%), feed intake (2.37-3.04%), feed conversion ratio (0.84-1.02), and somatic indices. The dietary LD or BFO supplementation also had marginal effects on fish body proximate composition, biochemical parameters, muscle texture, and water-holding ability, as well as the hepatic expression of lipid metabolism-related genes. Partial (2/3) replacement of added MFO by LD or BFO did not significantly reduce the muscle n-3 LC-PUFA content, indicating the n-3 LC-PUFA sparing effects of SFA and MUFA in LD and BFO. In general, dietary LD or BFO reduced the peroxidation level and led to significant changes in the muscle volatile flavor compound profile, which were probably attributed to the change in fatty acid composition. The results of this study evidenced that LD and BFO are good potential lipid sources for tiger puffer feeds.

Zebrafish Feed Intake: A Systematic Review for Standardizing Feeding Management in Laboratory Conditions.

Zebrafish are one of the most used animal models in biological research and a cost-effective alternative to rodents. Despite this, nutritional requirements and standardized feeding protocols have not yet been established for this species. This is important to avoid nutritional effects on experimental outcomes, and especially when zebrafish models are used in preclinical studies, as many diseases have nutritional confounding factors. A key aspect of zebrafish nutrition is related to feed intake, the amount of feed ingested by each fish daily. With the goal of standardizing feeding protocols among the zebrafish community, this paper systematically reviews the available data from 73 studies on zebrafish feed intake, feeding regimes (levels), and diet composition. Great variability was observed regarding diet composition, especially regarding crude protein (mean 44.98 ± 9.87%) and lipid content (9.91 ± 5.40%). Interestingly, the gross energy levels of the zebrafish diets were similar across the reviewed studies (20.39 ± 2.10 kilojoules/g of feed). In most of the reviewed papers, fish received a predetermined quantity of feed (feed supplied). The authors fed the fish according to the voluntary intake and then calculated feed intake (FI) in only 17 papers. From a quantitative point of view, FI was higher than when a fixed quantity (pre-defined) of feed was supplied. Also, the literature showed that many biotic and abiotic factors may affect zebrafish FI. Finally, based on the FI data gathered from the literature, a new feeding protocol is proposed. In summary, a daily feeding rate of 9-10% of body weight is proposed for larvae, whereas these values are equal to 6-8% for juveniles and 5% for adults when a dry feed with a proper protein and energy content is used.

Evaluation of fish meal replacement by Methylcoccus capsulatus protein in diets for juvenile Chinese softshell turtle (Pelodiscus sinensis)

The present study was to investigate the effects of Methylococcus capsulatus protein (MCP) replacing fish meal on the growth performance, immunity, and intestinal health of Chinese soft-shelled turtle (Pelodiscus sinensis). Four isonitrogenous (47.00% crude protein) and isolipidic (6.00% crude lipid) diets were formulated for an 8-week feeding trial. The fish meal group (FM) contained 55% fish meal. MCP was used to replace 10%, 15%, and 20% of the fish meal in the FM group to create MCP10, MCP15, and MCP20 treatment groups. No significant differences were observed in the weight gain, feed conversion efficiency, physical indicators, or muscle amino acid composition among all diet treatments (P > 0.05). The MCP15 group showed the best growth performance. There were no significant differences in serum biochemistry among the groups (P > 0.05), except for aspartate aminotransferase, which exhibited a significant linear increase trend with the increase of MCP replacement level (P = 0.049). In the MCP20 group, the complement C3 content, immunoglobulin M content, and lysozyme activity in serum were significantly lower than those in the FM, MCP10, and MCP15 groups (P < 0.05), showing a quadratic relationship characterized by an initial increase followed by a decrease as the MCP level in the feed increased (P < 0.05). The intestinal morphology in all treatment groups appeared normal and the expression levels of intestinal inflammatory cytokines showed no significant differences (P > 0.05). The community structure of the intestinal microbiota, as well as the phylum and genus composition underwent significant alterations in response to the MCP supplementation. The recommended practice for Chinese softshell turtle diet involves substituting 15% MCP for fish meal, which enhances growth, boosts immune response, and does not adversely affect serum biochemistry, amino acid composition, or intestinal health.

Effect of Temperature on the Nutritional Quality and Growth Parameters of Yellow Mealworm (Tenebrio molitor L.): A Preliminary Study

The nutritional quality of insects is related to many factors, including their rearing conditions. In this study, the effects of temperature on the contents of crude protein, lipids, ash, and amino acids and the body size and weight of Tenebrio molitor larvae were analysed. The larvae were reared with the occurrence of the first 20 pupae in a laboratory incubator at temperatures of 22, 25, and 28 °C. The results revealed that the weight (from 0.09 to 0.15 g), dry matter (DM) content (from 30.72 to 36.55 g/100 g), and fat concentration (from 22.46 to 36.01 g/100 g DM) of the larvae increased with increasing rearing temperature. In contrast, the crude protein content significantly decreased (from 64.33 to 54.41 g/100 g DM). Methionine was the limiting amino acid. The essential amino acid index ranged from 37% to 45%. Information about the effect of temperature on the growth and nutritional parameters of mealworms may contribute to the optimisation of mealworm-rearing technology.

(-)-Epigallocatechin-3-O-Gallate Regulates Muscle Growth, Antioxidant Status, and Nutritional Composition of Juvenile Common Carp (Cyprinus carpio L.)

Among the polyphenolic compounds commonly found in green tea, (-)-epigallocatechin-3-gallate (EGCG) is known to have various functions, including the promotion of antioxidant and myofiber growth in mammals. However, the effect of EGCG on common carp (Cyprinus carpio L.) remains poorly understood. To evaluate the role of EGCG on juvenile common carp, 255 fish (initial weight 17.33 ± 0.34 g) were fed with five experimental diets containing 0, 0.05, 0.25, 0.5, and 1 g/kg EGCG. The results showed that diet supplementation with 0.05–0.5 g/kg EGCG supplementation significantly enhanced the specific growth rate (SGR) and reduced the feed conversion ratio (FCR). Weight gain rate (WGR) was significantly enhanced in the 0.25 and 0.5 g/kg EGCG groups. As for antioxidants, 0.25–1 g/kg EGCG significantly reduced protein carbonyl (PC) content and upregulated superoxide dismutase (sod) gene expression in the muscle. As for muscle nutritional composition, 0.05–0.5 g/kg EGCG increased total amino acid (TAA) and flavor amino acid (FAA) contents, likely via the rapamycin (mTOR) signaling pathway. Muscle n-3 polyunsaturated fatty acids (n-3 PUFA) content was increased with 0.5 g/kg EGCG, presumably owing to the upregulation of fatty acyl elongase 5 (elovl5), long-chain fatty acyl-CoA synthetase 6 (acsl6), and peroxisome proliferator-actiated receptor α (pparα). Dietary EGCG (0.05–1 g/kg) significantly increased muscle hardness and chewiness, accompanied by an increase in myofiber density. EGCG supplementation (0.25–1 g/kg) increased the pH value and reduced lactate contents in the muscle. However, muscle crude lipid and hydroxyproline contents significantly decreased with 1 g/kg EGCG. Overall, quadratic regression analysis of WGR, SGR, TAA, and FAA showed that optimal EGCG (0.46–0.52 g/kg) dietary supplementation improved the growth and nutritional composition of juvenile common carp.

The effects of nano-curcumin on growth performance, feed utilization, blood biochemistry, disease resistance, and gene expression in European seabass (Dicentrarchus labrax) fingerlings

Phytochemicals are used in fish farming to reduce stress and combat diseases during intensification. Recently, nanotechnology has represented a paradigm shift in the aquatic feed industry to improve the solubility, availability, and efficacy of phytochemicals. The purpose of this research was to investigate the effects of dietary supplementation with nano-curcumin (CUNE) on the growth, feed utilization, body composition, blood biochemistry, antioxidant status, disease resistance to Vibrio parahaemolyticus (V. parahaemolyticus), and the expression of insulin-like growth factor 1 (IGF-1), growth hormone (GH), interleukin-10 (IL-10), and interlukin-1β (IL-1β) genes in European Seabass (Dicentrarchus labrax) fingerlings. Fish (6.02±0.01) were randomly divided into four equal groups and fed varying levels of CUNE: 0 (CUNE0), 50 (CUNE1), 60 (CUNE2), and 70 mg/kg (CUNE3) of nano-curcumin for 56 days, respectively. The inclusion of dietary CUNE significantly improved the growth indices (final body weight and weight gain, and specific growth rate) and feed utilization (improved feed intake and lower FCR) of European seabass fingerlings (p<0.05). However, CUNE inclusion had no significant effect on body composition including the percentages of dry mater, crude protein, crude lipid, and ash (p>0.05). All CUNE groups established an enhancement in blood hematology in a dose-dependent manner, with CUNE3 demonstrating the highest values. CUNE supplementation (70 mg/kg diet) produced the highest levels of total protein, albumin, globulin, and triglycerides, as well as the lowest levels of glucose, and hepatic enzymes (ALT, AST, and ALP; p<0.05) compared to other groups. Furthermore, the CUNE-supplemented groups showed significant improvements in superoxide dismutase, catalase, and glutathione peroxidase, while reducing malondialdehyde (p<0.05). Additionally, the consumption of CUNE increased the expression of IGF-1, GH, and IL-10 genes in a dose-dependent manner (p<0.05). Interestingly, fish fed 70 mg of CUNE in their diets had lower expression of the IL-1β gene compared to the other groups (p<0.05). When the fish were challenged with V. parahaemolyticus, the addition of CUNE in their diets resulted in reduced mortality rates. Therefore, nano-curcumin could be considered as a natural feed additive to promote growth, feed utilization, and bacteria resistance via supporting antioxidant status, serum metabolites, and the regulation of GH, IL-10, and IGF-1 in the hepatic tissues of European seabass fingerlings.

The regulation of AMPK pathway in liver abnormal lipid deposition caused by high carbohydrate diet in rice field eel

AMP-activated protein kinase-alpha 1 (AMPKα1) plays a vital role in glucose and lipid metabolism. Five isonitrogenous and isolipid diets with starch levels (15%, 20%, 25%, 30% and 35%) were formulated to study the modulation of AMPKα1 in hepatic lipid deposition induced by high gelatinized starch diet in rice field eel (Monopterus albus) (initial body weight, 30.00 ± 0.10 g) and the growth trial lasted for 8 weeks. The results showed that dietary gelatinized starch did not affect the growth performance of rice filed eel compared with S15 group. High gelatinized starch could induce AMPKα1 expression and glucose catabolism, and inhibit hepatic glycogen synthesis without effecting glucose content. Dietary ≥ 30% gelatinized starch began to dramatically suppress gluconeogenesis and promote the lipid synthesis, followed by a higher triglyceride (TG) and hepatic crude lipid. Dietary 20–30% gelatinized starch induced phosphorylation of AMPKα compared to 15% gelatinized starch diet, whereas 35% starch dramatically suppressed AMPKα phosphorylation together with unnormal increase in phosphorylation of forkhead box O1 A (FOXO1A) and acetyl-CoA carboxylase (ACC), TG content compared to 30% starch. In short, high gelatinized starch could induce AMPKα1 expression and promoted systemic metabolism, whereas dietary ≥ 25% gelatinized starch initially suppressed AMPKα1 activation and caused abnormal lipid deposition in liver of rice field eel.

Supplementing lysolecithin in corn-oil based diet enhanced growth and improved body biochemical composition in juvenile stellate sturgeon (Acipenser stellatus)

A 56-days nutritional trial was conducted to examine the influence of including a corn-oil based diet with lysolecithin (LL) on stellate sturgeon (Acipenser stellatus) juveniles. Fish were fed four experimental diets (44% crude protein, 15% crude lipid) containing graded levels of LL [0 (control), 0.5, 1 and 2%)]. One hundred and eighty juvenile fish (45.3 ± 0.1 g, mean ± standard deviation) were stocked in twelve 300 L-polyethylene tanks containing ground water at 18.9 ± 0.5°C. Feeds were offered to fish at apparent satiation four times daily. Fish fed 1% LL-supplemented diet had higher growth and better feed conversion ratio than the control group (P < 0.05). The amounts of protein and lipid levels in the whole body increased in fish fed LL-supplemented diets compared to control, whereas the levels of n-6 PUFA, particularly linoleic acid, increased in fish fed 0.5 and 1% LL-supplemented diets. Total long chain polyunsaturated fatty acids increased in fish fed 1% LL-supplemented diet. Regarding digestive enzymes, trypsin (alkaline pancreatic proteases) and pepsin (acid gastric protease) activities decreased with increasing LL in the diet. Overall, these results indicated that 1% LL is recommended for better growth performance of stellate sturgeon juveniles.

Effects of nuciferine on growth performance, body composition, lipid metabolism and antioxidant capacity of juvenile large yellow croaker (Larmichthys crocea) fed diets with high palm oil level

This study was conducted to explore the impacts of nuciferine (NF) on growth performance, body composition, lipid metabolism and antioxidant capacity of juvenile large yellow croaker (Larmichthys crocea) fed diets with high palm oil level. Five diets were formulated with fish oil (FO), palm oil (PO) and PO supplemented with 0.01%NF, 0.05%NF and 0.25%NF. After feeding for 10 weeks, the results showed that the growth performance (final body weight and specific growth rate) exhibited a significantly quadratic trend with the increase of NF addition, and the maximums were observed in PO supplemented with 0.05%NF group. Moreover, dietary PO diet with NF addition relieved the abnormal lipid accumulation (hepatosomatic index, crude lipid and triglyceride contents, total cholesterol contents, low-density lipoprotein-cholesterol contents in liver and serum) induced by PO diet. Simultaneously, NF addition inhibited PO diet-induced increase in the mRNA expressions of lipid synthesis-related genes and PO diet-induced activation of SREBP1. In addition, dietary PO diet with NF addition impeded PO diet-induced increase of hepatic MDA contents and recovered PO diet-induced inhibition of SOD and CAT activities. Similarly, NF addition alleviated PO diet-induced decrease in the mRNA expressions of antioxidant-related genes and PO diet-induced inhibition of SOD protein expression. Thus, addition of NF in PO diet might effectively ameliorate PO diet-induced growth retardation, lipid metabolism disorder and oxidative stress in croaker, and the optimal addition dose of NF in PO diet was approximately 0.05%.