Low Fish Meal Research Articles

Effects of tea tree essential oil supplementation in low fish meal diet on growth, lipid metabolism, anti-oxidant capacity and immunity of largemouth bass (Micropterus salmoides)

This study was conducted to investigate the effects of tea tree essential oil (TTO) supplementation in low fish meal diet on growth, lipid metabolism, anti-oxidant capacity and immunity of largemouth bass (Micropterus salmoides). Five low fish meal (175 g kg−1) diets with grade levels of TTO (0, 0.25, 0.5, 1 and 2 g kg−1) were formulated to feed largemouth bass (initial weight: 15.06 ± 0.05 g) for 56 days. The results indicated that supplementation of dietary 1 g kg−1 TTO could significantly improve the weight gain rate, specific growth rate and protein deposition ratio, and decrease the feed conversion rate. The activities of gastric lipase and intestinal trypsin were enhanced by dietary TTO. The width of the intestinal villus was significantly elevated with dietary TTO level. In lipid metabolism parameters, the whole-body crude lipid content was increased and the liver crude lipid content was decreased in TTO treatment groups. The expression of acetyl-CoA carboxylase beta was downregulated, and the mRNA levels of peroxisome proliferator activated receptor alpha and carnitine palmitoyl-transferase 1 were upregulated in the liver by the addition of TTO. The contents of total cholesterol, triglyceride and low-density lipoprotein cholesterol significantly decreased, and the content of high-density lipoprotein cholesterol significantly increased in serum by dietary TTO. In anti-oxidative parameters, catalase activities in the liver and superoxide dismutase activities in the liver, intestine and serum were elevated with dietary TTO level. Malondialdehyde and protein carbonyl contents in the liver, intestine and serum showed the opposite trend. The nf-e2-related factor 2 (Nrf2) signaling pathways in the liver and intestine were triggered by dietary TTO supplementation. In the immune indices, the contents of total protein and albumin were improved, and the contents of glucose, aspartate aminotransferase and alanine transaminase were declined in TTO treatment groups. However, hepatocyte swelling and nuclear migration were found in the liver sections of all groups. After Aeromonas hydrophila administration, the toll-like receptor 2 (TLR2) signaling pathway was activated in the head-kidney, liver and intestine, and the expression levels of interleukin 10 and transforming growth factor beta 1 were increased in the head-kidney, spleen, liver and intestine by dietary TTO. In conclusion, dietary TTO in low fish meal diet could improve growth, anti-oxidant capacity and immunity, and reduce lipid deposition in the liver and serum of largemouth bass. The optimal level of TTO in low fish meal diet of largemouth bass ranged from 1.33 to 1.34 g kg−1.

Effects of three feed attractants on the growth performance and meat quality of the largemouth bass (Micropterus salmoides)

The trial was conducted to investigate the effects of limonene, allicin and betaine supplementation in low fish meal (FM) diet on growth performance, antioxidant capacity, meat quality and intestinal health in largemouth bass (M. salmoides). The biting-balls test and feeding trial were successively conducted. For the one, the results of the biting-ball test showed that with the increase of the concentration of the three attractants, the attracting effect firstly increased, then decreased, and the effect reached maximum at 0.2% concentration. (P < 0.05). Further, a 9-week feeding trial was conducted using five diets, including a basal diet with 30% and 40% fish meal without attractant, 30% fish meal supplemented with 0.2% limonene, 0.2% allicin or 0.2% betaine (the diets were named FM30, FM40, FM30 + L, FM30 + A, FM30 + B, respectively). The results demonstrated that adding limonene, allicin and betaine at concentration of 0.2% to the low fish meal feed could improve final body weight, weight gain rate, and specific growth rate of M. salmoides but only in 4 weeks (P > 0.05). Besides, dietary supplementation with attractants could significantly reduce the content of MDA in serum and liver, and increase the activity of GSH in liver (P < 0.05). Compared with FM30 group, the supplementation with limonene, allicin or betaine diet had higher pH, redness (a*), yellowness (b*) (P > 0.05), and lower refrigeration loss, cooking loss values (P < 0.05). Furthermore, supplementation with attractants groups had higher values for villus height, lamina propria, crypt depth, submucous layer, and serous layer (P < 0.05). Taken together, these results indicated that limonene, allicin and betaine had a time effect on the growth performance, and could improve antioxidant capacity, meat quality and intestinal health of M. salmoide.

Zootechnical performance, immune response, and resistance to hypoxia stress and Vibrio harveyi infection in Pacific white shrimp (Litopeneaus vannamei) fed different fishmeal diets with and without addition of sodium butyrate

The dietary effect of a chemically protected sodium butyrate, Butirex®C4 (BU), on growth performance, digestive enzymes activity, immunity, gut microflora, and resistance against hypoxia stress and infectious disease were studied in Pacific white shrimp fed different levels of fishmeal (FM) diets in earthen outdoor ponds. Nine isonitrogenous and isolipidic experimental diets were formulated to contain different levels of FM (45 %, 30 %, and 15 %) and enriched with the incremental levels of BU (0, 0.3%, and 0.6%). After 60 days, the shrimp fed diets containing 45% and 30 % FM along with 0.3 % and 0.6 % BU, respectively, showed higher levels of final weight and weight gain, while, the group fed diet with 15 % FM free from BU showed the highest level of feed conversion ratio. The levels of protease and trypsin activity significantly decreased in the group fed 15 % FM without BU, while the administration of BU improved the digestive enzymes activity in low FM diets. The total hemocyte count, phenoloxidase, and lysozyme were negatively affected by decreasing levels of FM in the diets, but BU-supplemented diets improved these parameters. The dietary administration of BU increased lactic acid bacteria and decreased total Vibrio sp. counts in the intestine of shrimp fed different levels of FM. Although the diets with low levels of FM had no significant effect on the hypoxia stress tolerance, the cumulative mortality was decreased in the low FM groups fed with different BU levels. The mortality of shrimp against Vibrio harveyi infection was notably decreased in BU-added groups compared to the groups that did not receive BU in their diets. Overall, dietary BU administration at 0.6 % mitigates the adverse impacts of the diets with the lowest FM (15 %) on overall performance and immunity in Pacific white shrimp.

Effects of Dietary Nucleotide Supplementation on Performance, Profitability, and Disease Resistance of Litopenaeus vannamei Cultured in Indonesia under Intensive Outdoor Pond Conditions.

Simple SummaryIn Indonesia, there is an increasing tendency to use vegetable protein sources as a replacement for fish meal in diets for Pacific white shrimp (PWS), Litopenaeus vannamei. This; however, involves a negative impact on shrimp health given the high content of anti-nutritional factors in such protein sources. As dietary nucleotides modulate the immune response, they might be able to counteract this effect by enhancing PWS immunity and improving their performance and resistance to diseases. In this study, we evaluated the effects of nucleotide supplementation in PWS receiving diets in which fish meal had been partially replaced with soybean meal. Our data show that dietary nucleotide supplementation leads to improved growth performance and profitability, as well as to higher resistance to Vibrio harveyi. These positive results indicate that dietary nucleotides could constitute a useful tool in the production of shrimp cultured under intensive open-pond systems.This study evaluated the effects of dietary nucleotide supplementation in Pacific white shrimp, Litopenaeus vannamei, cultured in Indonesia. A total of 22,500 shrimp receiving diets in which fish meal (FM) had been partially replaced with vegetable protein sources were classified into five study groups (4500 shrimp/group) and received different diets for 110 days: 10FM (control group; 10% FM), 6FM (6% FM—low FM and no nucleotide supplementation), 10FMN (10% FM; 0.1% nucleotides), 8FMN (8% FM; 0.1% nucleotides) and 6FMN (6% FM; 0.1% nucleotides). Growth performance, body composition, total hemocyte count (THC), lysozyme activity, and hepatopancreas histopathology were assessed. Organoleptic evaluation and profitability assessments were also performed. In addition, shrimp resistance to a Vibrio harveyi challenge was studied in shrimps after having received the diets for 30 days. Results showed that reducing FM had a negative impact on growth performance and hepatopancreas morphology. Adding nucleotides resulted in better performance and profitability, a healthier histomorphological appearance of the hepatopancreas, and significantly higher survival rates upon challenge with V. harveyi, while it did not negatively affect organoleptic parameters. In conclusion, nucleotide supplementation could be useful for optimizing performance, profitability, and disease resistance in shrimp cultured under intensive outdoor pond conditions.

A Natural Gas Fermentation Bacterial Meal (FeedKind®) as a Functional Alternative Ingredient for Fishmeal in Diet of Largemouth Bass, Micropterus salmoides.

A 10-week growth study was conducted to evaluate the effect of a natural gas fermentation bacterial meal (FeedKind®, FK) as a fishmeal (FM) alternative in largemouth bass (Micropterus salmoides) (48.0 ± 0.03 g). Four isonitrogenous and isoenergetic diets were formulated including one commercial control (C, 42% FM) and three experimental diets with gradient FK of 3% (FK3, 29%FM), 6% (FK6, 26%FM) and 9% (FK9, 23%FM), respectively. FK-fed groups showed significantly higher SR than that of C group. The WGR and SGR of fish fed FK3 and FK6 were significantly higher than those of FK9, but not statistical different from the C group. FK-fed groups showed higher apparent digestibility coefficients of dry matter and nutrients. Further, FK-fed groups increased the ratio of SOD/MDA in the plasma and liver, and the upregulation of intestinal Keap1 and downregulation of HIF1α was found in FK3. Furthermore, FK-fed groups showed higher microbial richness and diversity. Pearson correlation analysis found that antioxidant relevant biomarkers were negatively correlated with the relative abundance of certain potential beneficial bacteria. In conclusion, supplemented up to 3–6% FK replacing FM in a low FM diet of largemouth bass could increase growth, survival rate, antioxidant capacity, and improve gut microbiota.

Assessment of Conventional and Low Gossypol Cottonseed Meal as Alternative Protein Sources in Low-Fishmeal Diets of Hybrid Grouper (Epinephelus fuscoguttatus♀× Epinephelus lanceolatus♂): Growth, Feed Utilization, Gut Histology, and Immunity.

Simple SummaryThe rapid and sustained growth rate of global aquaculture has forced the aquaculture industry to explore alternative and more sustainable feed ingredients. Plant protein ingredients are promising substitutions for fish meal in the aquaculture industry. The current study aimed to investigate the potential influence of replacing poultry by-product meal protein with conventional cottonseed meal protein (CCMP) or low-gossypol cottonseed meal protein (LGCMP) on growth, feed utilization, gut micromorphology, and immunity of hybrid grouper (Epinephelus fuscoguttatus ♀ × Epinephelus lanceolatus ♂) juveniles fed low fish-meal (18.53%, dry matter) diets. Results demonstrated that, without any reduction in fish performance, 80% dietary PBMP could be replaced by CCMP, while this replacement level was 40% for LGCMP. Survival remained unaffected in all dietary treatments, and no fish mortality was observed during the growth trial. These results suggest that cottonseed meal could be a suitable alternative protein source for hybrid grouper farming.A 9-week growth trial was carried out to assess the influence of replacing poultry by-product meal protein with conventional cottonseed meal protein (CCMP) or low gossypol cottonseed meal protein (LGCMP) on growth, feed utilization, gut micromorphology, and immunity of hybrid grouper (Epinephelus fuscoguttatus ♀ × Epinephelus lanceolatus ♂) juveniles fed low-fish meal (18.53%, dry matter) diets. Eleven experimental diets were prepared. The control diet (PBMP) contained 46.15% poultry by-product meal protein. Both conventional cottonseed meal protein (CCMP) and low-gossypol cottonseed meal protein (LGCMP) were used in replacement ratios of 20, 40, 60, 80, and 100% of poultry by-product meal protein (PBMP) from the control diet, forming ten experimental diets (CCMP20, CCMP40, CCMP60, CCMP80, CCMP100, LGCMP20, LGCMP40, LGCMP60, LGCMP80, and LGCMP100). Results demonstrated that weight-gain percentage (WG%) was not different between different sources of cottonseed meal (CCMP and LGCMP). However, values of WG% significantly differed among different replacement levels, with CCMP80 and LGCMP40 having significantly higher values compared to other treatments. Fish fed CCMP80 and LGCMP40 exhibited higher protein efficiency ratios (PERs) than fish fed other experimental diets. The regression analysis from a second-order or third-order polynomial model based on WG% showed that the optimal PBMP replacement levels by CCMP and LGCMP are 74% and 33%, respectively. The whole-body lipid contents remarkably decreased as dietary CCMP or LGCMP inclusion levels increased. The relative mRNA expression of insulin-like growth factor-1(IGF-1) in liver was higher in fish fed CCMP80 and LGCMP40 diets compared to fish fed other diets. Generally, in low-FM diets of hybrid grouper, CCMP and LGCMP could replace 74% and 33% of PBMP, respectively.

Effects of dietary tuna hydrolysate supplementation on feed intake, growth performance, feed utilization and health status of Asian sea bass ( Lates calcarifer ) fed a low fish meal soybean meal‐based diet

This study aimed to examine the effects of dietary tuna hydrolysate supplementation on feed intake, growth, feed utilization and health status of Asian sea bass. Experimental diets included a high fish meal-based diet (HFM diet) containing 45% of fish meal, a low fish meal-based diet (LFM diet) in which 55% of fish meal protein was replaced with soybean meal and the LFM diet coated with 2.5% tuna hydrolysate (LFM + TH diet). Fish were fed diets for 8 weeks. Growth rate, feed intake, feed efficiency, protein efficiency ratio, nitrogen retention, intraperitoneal fat and serum albumin of fish-fed LFM + TH diet were significantly higher than those of fish-fed LFM diet (p < 0.05). No significant differences in carcass chemical compositions, serum cholesterol, triglyceride, aspartate aminotransferase, lysozyme activity, superoxide dismutase and trypsin and lipase activities were found in hepatopancreas and anterior intestine among the dietary treatments. Fish-fed LFM + TH diet displayed a longer length of distal intestine villi than those of fish-fed LFM + TH diet. No histopathological changes in the liver were observed in this study. The results suggest that dietary supplementation of 2.5% tuna hydrolysate is sufficient to enhance the diet palatability, which can increase the replacement levels of fish meal protein with soybean meal up to 55% in a low fish meal soybean meal-based diet without negative impacts on feed intake and growth performance of juvenile Asian sea bass.

Dietary fish oil levels modulated lipid metabolism, immune response, intestinal health and salinity stress resistance of juvenile Penaeus monodon fed a low fish-meal diet

Dietary fish meal (FM) and fish oil (FO) replacement are crucial for the sustainable development of aquaculture. An eight weeks feeding trial was conducted to evaluate the potential replacing FM with soy protein concentrate, and the suitable FO level for a low FM diet of Penaeus monodon. A diet containing 25% FM was used as the control (C diet), and three other diets were formulated to contain 15% FM, and supplemented with 3%, 2%, 1% FO [high FO (HF), medium FO (MF) and low FO (LF), respectively]. The experiment was conducted in quadruplicates (30 shrimp per replicate, average weight 1.00 ± 0.01 g). The results indicated that besides the final body weight, there were no differences in weight gain, feed efficiency and survival rate observed among the four groups. The results of the acute salinity stress showed that shrimp fed the C and MF diets showed a similar survival rate, which was significantly higher than those fed a LF diet. Shrimp that were fed HF, MF and LF diets showed a lower level of fatty acid transport-related mRNA expression in the hepatopancreas, compared with those fed the C diet. Shrimp fed HF, MF and LF diets showed lower expression levels of superoxide dismutase, endoplasmic reticulum protein 57 and immune deficiency (IMD) in the hepatopancreas than those fed the C diet. Shrimp that were fed a LF diet showed the lowest expression levels of inhibitor of apoptosis proteins, Toll and tumor necrosis factor receptor associated factor 6 (TRAF6) in the hepatopancreas, as well as the highest expression levels of Toll, extracellular signal-regulated kinase, Relish and TRAF6 in the intestine among four groups. Intestinal microstructure damage was observed in shrimp that were fed a LF diet, and intestinal endoplasmic reticulum (ER) swelling was observed in shrimp fed MF and LF diets. In conclusion, these results indicated that the growth performance of shrimp was not affected when the FM and FO contents decreased, whereas a low content of FM negatively influenced the immune response in shrimp by modulating IMD and ER stress related gene expression. Under low FM conditions, a suitable dietary FO level would benefit to the lipid transport, hepatopancreas and intestine health, as well as the immune response of shrimp.

Supplementation of a Multienzyme Complex, an Organic Acid-Essential Oil Complex, and Prebiotic Alone or in Combination Affects Growth, Nutrient Utilization, and Immune Function of Rainbow Trout (Oncorhynchus mykiss)

Dietary supplementation of functional additives is an effective strategy to improve the nutritive value of low fish meal diets for fishes. The present study is aimed at investigating the dietary effects of a multienzyme complex, an organic acid-essential oil complex and prebiotic on growth, immune function, and intestinal health of rainbow trout (Oncorhynchus mykiss). A positive control diet (PC) and a negative control diet (NC) were formulated to contain 200 g/kg and 100 g/kg of fishmeal, respectively. Seven other diets were formulated by supplementing a multienzyme complex (MC, 0.125 g/kg), organic acid-essential oil complex (OEC, 0.5 g/kg), and prebiotic (P, 2 g/kg) alone or in combination to the NC diet (MC, OEC, P, MC+OEC, MC+P, OEC+P, MC+OEC+P). All diets were formulated to be isoproteic (434.3 g/kg-439.1 g/kg) and isolipidic (119.2 g/kg-125.9 g/kg) and fed to rainbow trout of 7.66 ± 0.05 g for 56 days. The weight gain, apparent digestibility coefficient of dry matter, protein efficiency ratio, and protein retention efficiency were significantly increased, and feed conversion ratio was significantly decreased by the three additives alone or in combination ( P &lt; 0.05 ) compared to the NC. No significant differences in growth performance and feed utilization were observed among the treatment groups. Compared to the NC group, serum alanine transaminase, aspartate transferase activities, and malondialdehyde content reduced significantly, while serum superoxide dismutase increased in all except for the MC group, and alkaline phosphatase and lysozyme activity increased in all except for the MC and MC+P groups ( P &lt; 0.05 ). The foregut protease activity of the MC+P and OEC+P groups and the amylase activity of the OEC and MC+OEC groups were significantly higher than those of the NC group ( P &lt; 0.05 ). The villus height of P, MC+OEC, and OEC+P groups, the villus width of MC group, and the muscle thickness of MC, MC+OEC, and MC+OEC+P groups were also significantly higher than those of the NC group ( P &lt; 0.05 ). Compared to the PC group, the richness and diversity of intestinal microorganisms in the NC group and all the supplemented groups were significantly reduced ( P &lt; 0.05 ), but no differences among them ( P &gt; 0.05 ). In conclusion, the individual or combined supplementation of multienzyme complex, organic acid-essential oil complex, and prebiotic in a low fish meal diet (100 g/kg) improved the growth performance, nutrient utilization, and immune function of rainbow trout, but no synergistic effects were observed in the combination of the three supplements.

Beneficial effects of phytase and/or protease on growth performance, digestive ability, immune response and muscle amino acid profile in low phosphorus and/or low fish meal gibel carp (Carassius auratus gibelio) diets

A 10-week feeding trial was conducted to investigate the effects of individual and combined inclusion of phytase and protease on the growth performance, digestive ability, immune response and muscle amino acid profile of gibel carp (Carassius auratus gibelio) fed low phosphorus (LP) and/or low fish meal (LFM) diets. Seven experimental diets were designed: 1) Normal diet [PC, 15 g/kg Ca(H2PO4)2 and 80 g/kg fish meal], 2) Low P diet [10 g/kg Ca(H2PO4)2 and 80 g/kg fish meal], 3) LP + 0.4 g/kg phytase diet (LP + Ph), 4) Low fish meal diet [LFM, 15 g/kg Ca(H2PO4)2 and 50 g/kg fish meal], 5) LFM + 0.5 g/kg protease diet (LFM + Pr), 6) Low P and Low fish meal diet [LP-LFM, 10 g/kg Ca(H2PO4)2 and 50 g/kg fish meal] and 7) LP-LFM + 0.4 g/kg phytase +0.5 g/kg protease diet (LP-LFM + Ph + Pr). The results showed that the growth performance, whole body composition, nutrient digestibility, immunological indices, and muscle amino acid contents of gibel carp fed the LP, LFM and LP-LFM diets were dramatically lower than those of carp fed the normal diet (P<0.05). However, compared the LP-LFM, LFM and LP groups, dietary addition of phytase + protease, protease and phytase, respectively, (1) improved the special growth rate (SGR), weight gain rate (WGR), ADC of dry matter, crude protein and P; (2) upregulated the activities of lipase, trypsin, amylase and chymotrypsin in the liver and intestine; (3) increased liver lysozyme (LZM), superoxide dismutase (SOD), glutathione peroxidase (GPx) and total antioxidant capacity (T-AOC) levels, intestinal secreted immunoglobulin A (sIgA), complement 4 (C4) and C3 levels; (4) increased the contents of amino acids, for example, valine, leucine and methionine, in the muscle. Moreover, when both phytase and protease were added simultaneously, they had a better promoting effect than when individual added. It can be concluded that a reduction of dietary P and fish meal for gibel carp has side effects on growth performance, while phytase and protease could mitigate these effects by improving the digestive ability and immune response of gibel carp.

Effects of Lower Fishmeal With Hydrolyzed Fish Protein Powder on the Growth Performance and Intestinal Development of Juvenile Pearl Gentian Grouper (Epinephelus fuscoguttatus ♀ and Epinephelus lanceolatus ♂)

The effect of hydrolyzed fish protein powder (HFP) on the growth, intestinal development, gene mRNA expression, and enzyme activity in the intestine and liver of juvenile hybrid grouper (Epinephelus fuscoguttatus ♀ and Epinephelus lanceolatus ♂) was assessed after an 8-week feeding trial. Seven isonitrogenous (50%) and isolipidic (9%) diets were fed to hybrid grouper with 0% (CT), 1% (H1), 1.5% (H2), 2% (H3), 2.5% (H4), 3% (H5), and 4% (H6) HFP. No significant difference (p &amp;gt; 0.05) in weight gain rate (WGR), specific growth rate (SGR), feed conversion ratio (FCR), and survival rate (SR) was observed in all the groups. The crude protein content in the H6 group was significantly higher than in the other groups (p &amp;lt; 0.05). Intestinal lipase and trypsin activity were significantly higher in H3 and H5 groups (p &amp;lt; 0.05). In the serum, superoxide dismutase (SOD) activity was significantly higher in H5 and H6 groups, while malondialdehyde (MDA) activity was lower (p &amp;lt; 0.05) compared to other treatments. Insulin-like growth factor (IGF-I) and target of rapamycin (TOR) mRNA expression levels in the intestine and muscle were significantly higher in the H2 group and H1 group (p &amp;lt; 0.05), respectively. The most abundant intestinal bacteria found at the genus level are Acinetobacter, Vibrio, and Flavobacteriaceae. The villus was significantly longer in hybrid grouper fed with different levels of HFP compared to the control, and fish in the H2 group had thicker intestinal muscle compared to the other groups (p &amp;lt; 0.05). In conclusion, the addition of HFP to the low fishmeal (FM) diets of juvenile grouper improved the intestinal development and increased the levels of intestinal digestive enzymes.

Effects of Taurine Supplementation on Growth, Feed Utilization, Antioxidant Capacity, and Intestinal Microflora of Largemouth Bass Fed a Low Fish Meal Diet

AbstractThe present study was conducted to examine the effects of taurine supplementation on feed intake, growth, feed utilization, body composition, waste output, hepatic antioxidant enzymes, and intestinal microflora of Largemouth Bass Micropterus salmoides that were fed a low fish meal diet. Three isoproteic (49% crude protein) and isolipidic (9.5% crude lipid) diets were formulated: one diet contained 40% fish meal and served as the control (FM diet), and 60% of the fish meal in the FM diet was replaced by soybean meal either without taurine supplementation (SBM diet) or with 0.5% taurine supplementation (SBM+T diet). Lower feed intake, final body weight, weight gain, condition factor, and hepatosomatic index and a higher feed conversion ratio (FCR) were found in fish that received the SBM diet compared to fish that were fed the FM diet, but no significant difference was found in feed intake, final body weight, weight gain, FCR, condition factor, or hepatosomatic index between fish in the FM and SBM+T diet groups. No significant differences were found in nitrogen retention efficiency, body composition, nitrogen waste, or activities of total antioxidant capacity, superoxide dismutase, and glutathione peroxidase among fish fed the different test diets, and the alpha diversity of intestinal microbiota also did not differ among diet groups. The abundance of Proteobacteria and Firmicutes increased while the abundance of Fusobacteria decreased in the SBM diet group relative to the FM diet group; in contrast, dietary taurine (SBM+T diet) restored the abundance of Proteobacteria to a level similar to that in fish receiving the FM diet. This study suggests that the dietary fish meal level for Largemouth Bass can be reduced from 40% to 16% if soybean meal is used as an alternative protein with 0.5% taurine supplementation.

Effects of nutritional conditioning during first feeding and selective breeding with a low fish meal diet on the growth performance of juvenile rainbow trout Oncorhynchus mykiss

Effects of nutritional conditioning during first feeding and selective breeding with a low fish meal diet on the growth performance of juvenile rainbow trout <i>Oncorhynchus mykiss</i>

Modulation of intestinal health and hepatic vacuolation in gilthead sea bream (Sparus aurata) juveniles by a mixture of dietary esterified butyrins, emulsifiers from plants and yeast extracts at low and high fish meal inclusion

This study examined the modulatory effect of two commercial feed additives, Lumance® (0.2% and 0.5%) and Novigest® (0.4%), on the growth and microscopic structure of the intestine and liver of juvenile gilthead sea bream (Sparus aurata), when added to high (HFM-0) and low fish meal (LFM-0) diets. Lumance® was added only in the HFM-0 diet (HFM-0.2 and HFM-0.5), while a mixture of the two additives was used in the LFM-0 diet (LFM-0.6: 0.2% Lumance® + 0.4% Novigest® and LFM.0.9: 0.5% Lumance® + 0.4% Novigest®). Fish fed the HFM diets exhibited the highest overall growth, and significant differences were recorded in the specific growth rate (SGR), daily growth index (DGI), feed conversion ratio (FCR) and thermal growth coefficient (TGC), between the HFM and LFM dietary treatment groups. Supplementation of the additives had no effect on the growth performance in either of these groups. The analysis of the intestinal histomorphometric measurements showed signs of intestinal inflammation in the fish fed the LFM-0 diet. The addition of the two additives exhibited some modulatory effects, particularly increased intestinal villi length and lamina propria width in the mid-intestine. An increased number of intraepithelial cells and mucus production was also observed, as well as a decrease in hepatic vacuolation in the LFM-0.6 and LFM-0.9 groups, but not at a statistically significant level.

Lactobacillus spp. fermented soybean meal partially substitution to fish meal enhances innate immune responses and nutrient digestibility of white shrimp (Litopenaeus vannamei) fed diet with low fish meal

To accomplish the goal of sustainable aquaculture, substitution of fish meal (FM) with available and effective alternative ingredients is necessary. The present study evaluated the effects of fermented soybean meal (FSBM) substituted to FM on growth, innate immune responses, nutrient digestibility, and morphological changes in hepatopancreas of white shrimp Litopenaeus vannamei, fed a low FM diet. The FM protein was replaced by FSBM at 0%, 25% (25% FSBM), 50% (50% FSBM), 75% (75% FSBM), and 100% (100% FSBM) in the control diet (including 15% FM). Experimental diets were each fed in triplicates to juvenile shrimp with initial weight of 5.53 g in a closed recirculation system for eight weeks. Shrimp fed different diets exhibited similar (p > 0.05) growth performance and morphology in hepatopancreas. Shrimp fed the 75% FSBM diet had higher total hemocyte count than other dietary groups. Shrimp fed the 75% FSBM diet exhibited the highest phenoloxidase (PO) activity, followed by shrimp fed 50% FSBM and 100% FSBM diets, and lowest in shrimp fed the control and 25% FSBM diets. Apparent digestibility of dry matter, protein and lipid showed the highest performance in shrimp fed the 75% FSBM diet compared with other dietary treatments. Results indicate that FSBM can completely replace fish meal protein without any negative effects on growth and morphology in hepatopancreas. The adequate replacement levels is suggested at 75% to improve innate immune responses and nutrient digestibility for white shrimp.

Replacing poultry by‐product meal protein with soybean protein isolate in low fishmeal diets for juvenile hybrid grouper ( Epinephelus fuscoguttatus ♀ × Epinephelus lanceolatus ♂)

A 7-week growth trial was conducted to assess the potential of using soybean protein isolate (SPI) to replace poultry by-product meal (PBM) protein in low fishmeal (FM) diets for juvenile hybrid grouper (Epinephelus fuscoguttatus ♀ × Epinephelus lanceolatus ♂). Seven isoproteic (490 g kg−1) and isolipidic (90 g kg−1) experimental diets were formulated, including six low FM diets and a high FM diet (HFMP). The low FM diets contained 0, 74.8, 149.7, 224.5, 299.4 and 374.2 g kg−1 SPI, replacing approximately 0%, 20%, 40%, 60%, 80% and 100% of the PBM protein (designated as SPIP0, SPIP20, SPIP40, SPIP60, SPIP80 and SPIP100, respectively). Each diet was hand-fed to triplicate groups of 12 hybrid grouper juveniles (average initial body weight: 14.30 ± 0.1 g per fish). After being fed for 7 weeks, fish fed with HFMP and SPIP60 showed significantly higher (p < .01) weight gain percentage (WG%), protein efficiency ratio and protein productive value than fish fed with other experimental diets. These three parameters were elevated with the increment in PBM protein (PBMP) replacements, reaching the peak value at the 60% replacing level, and then, they were significantly reduced at the 80% or 100% replacing level. Analysis of the two-slope straight broken-line model showed that the maximum PBMP replacement level by SPI protein (SPIP) at the intercept value of WG% was estimated to be 60%. Feed conversion ratio showed an opposite tendency of variation to WG%. Fish fed with SPIP80 and SPIP100 displayed lower mRNA levels of hepatic insulin-like growth factor-1, hypothalamus neuropeptide Y and head-kidney nuclear factor erythroid 2-related factor 2 than fish fed with other experimental diets. Generally, 60% of PBM protein could be replaced with SPI protein in low FM diets for hybrid grouper.

Effects of fermented soybean meal and guanosine 5'-monophosphate on growth, intestinal health and anti-stress capability of Penaeus vannamei in low fish meal diet

Substitution of fishmeal by plant protein source has been one of the most concerned issues in aquaculture. The present study aimed to evaluate the replacement of fishmeal by fermented soybean meal (FSM) and supplementation of nucleotide, guanosine 5′-monophosphate (5′-GMP), on growth, intestinal health and anti-stress capability in Penaeus vannamei. Six diets were formulated to contain three replacement levels of fish meal by FSM (0, 22.22% and 44.44%) with or without 5′-GMP (0.1%). The feeding trial lasted for 8 weeks, followed by the hypoxia exposure. The results indicated that 44.44% of fishmeal substituted by FSM did not have negative effects on growth and digestive enzymes activities in shrimp, while it significantly affected intestinal micromorphology by decreasing fold height, enterocyte height and microvillus height. 22.22% of Fishmeal substituted by FSM had higher genes expression of target of tor, s6k and 4ebp1 suggesting the potential improvement in growth. Application of FSM influenced intestinal microbiota of shrimp with the changes in microbiota composition, community diversity and richness. Metabolites and enzymes associated with stress response including MDA, LD, SOD, T-AOC, GSH and GSH-PX were all markedly increased after hypoxia stimulus, and SOD, T-AOC and GSH-PX was significant higher in the shrimps fed without 5′-GMP in high fishmeal diet. Lgbp and hsp70 mRNA level were also higher in the shrimp after hypoxia stimulus especially fed with 5′-GMP in low fishmeal diet, while sp and pe were lower expressed in the shrimps after hypoxia stimulus. Finally, our results determined that FSM had a fishmeal sparing effect for the diet of P. vannamei, and the supplementation of 5′-GMP in the diet slightly benefited growth, gut health and anti-stress capacity for P. vannamei.

Growth performance, apparent digestibility coefficients and digestive enzyme activities of Pacific white shrimp, Penaeus vannamei fed low fishmeal diets supplemented with DL‐methionine and phytase

An eight-week growth trial and a four-week digestibility trial was undertaken to assess the impact of DL-methionine and phytase supplementation on growth performances, apparent digestibility coefficients (ADC), phosphorus retention and digestive enzyme activities of Penaeus vannamei. Five treatment groups in three replicates fed with a control diet (fishmeal 200 g/kg), and four low fishmeal (50 g/kg) diets with soy protein concentrate-soybean meal protein viz., SPC1 (without supplementation), SPC 2 (DL-methionine), SPC 3 (Phytase) and SPC4 (DL-methionine and phytase). SPC 2 had significantly improved (p < .05) the weight gain (5.79 ± 0.12), FCR (1.53 ± 0.06) and SGR (3.21 ± 0.06) than other low fishmeal diets, but not significantly different to that of SPC 4 and control. SPC 2 also showed significantly higher protease activity. P retention was significantly higher in SPC 2 than SPC 1, SPC 3 and control, however, not significantly different from SPC 4. Faecal phosphorus load was significantly reduced in SPC 2 than SPC 1 and control. Protein digestibility was significantly higher in SPC 2 and SPC 4, whilst phosphorus digestibility was significantly higher in SPC 4. Thus, it is concluded that the supplementation of DL-methionine is essential for the overall better performances of P. vannamei in low fishmeal diets and phytase for improving phosphorus digestibility.

Supplementing Chitosan Oligosaccharide Positively Affects Hybrid Grouper (Epinephelus fuscoguttatus ♀ × E. lanceolatus ♂) Fed Dietary Fish Meal Replacement With Cottonseed Protein Concentrate: Effects on Growth, Gut Microbiota, Antioxidant Function and Immune Response

Oligosaccharides have recently received much attention from researchers owing to their multiple biological activities. This study was conducted to investigate the effects of a diet with reduced fish meal and chitosan oligosaccharide (COS) supplementation on a hybrid grouper (Epinephelus fuscoguttatus ♀ × E. lanceolatus ♂). Seven isonitrogenous and isolipidic types of diet were formulated to feed the groupers for 56 days. To prepare the feed, a reference diet (FM group) containing 55% fish meal was used. Concentrated cottonseed protein (CPC) was used to replace 45% of the fish meal protein, and different COS supplementation levels (0, 0.2%, 0.4, 0.6, 0.8, and 1%) were added. After an 8-week breeding trial, Vibrio harveyi bacteria were injected into the groupers for a 7-day challenge test. The results showed that the FM and COS0.4 groups showed the best growth performance among the groups (p &amp;lt; 0.05); however, there was no significant difference in the survival rate (p &amp;gt; 0.05). Unlike in the FM group, adhesion and breakage of the intestinal plica occurred in the COS0 group. The height and width of the gut fold reached maximum values in the COS0.4 group (p &amp;lt; 0.05). Microbiome sequencing suggested that there was a stable microbiota core in the gut of the groupers. With increasing COS levels, the abundance of both beneficial bacteria and conditional pathogens increased; the activities of serum glucose oxidase, catalase, and total superoxide dismutase also increased (p &amp;lt; 0.05). In the gut tissue, the activities of glutathione peroxidase, glutathione reductase, and glutamine increased first but then decreased (p &amp;lt; 0.05); the contents of lysozyme, acid phosphatase, complements C3 and C4, and IgM showed upward trends (p &amp;lt; 0.05). Compared with that in the FM group, the expression of IL-1β and TNF-α in the COS0 group was upregulated. Gene expression levels of TLR22, TGF-β, and Nrf2 increased first but then decreased with COS supplementation levels (p &amp;lt; 0.05). COS supplementation reduced the cumulative mortality of the groupers in the challenge test (p &amp;lt; 0.05). In general, the results of this study demonstrated that dietary COS supplementation enhanced growth performance, intestinal health, and antioxidant and immune responses of groupers fed with a low-fish meal diet. The optimal and acceptable levels of COS supplement were 0.45 and 0.4–0.6%, respectively; these values can provide a reference for developing aquatic prebiotics.

Optimizing the fatty acid profile of novel terrestrial oil blends in low fishmeal diets of rainbow trout (Oncorhynchus mykiss) yields comparable fish growth, total fillet n-3 LC-PUFA content, and health performance relative to fish oil

Identifying and effectively utilizing suitable, novel, terrestrial oil sources either alone or as blends to replace fish oil (FO) is a prerequisite for improving the sustainability of global aquaculture. Therefore, the present study evaluates several novel terrestrial oil blends (TOBs), optimized for their fatty acid profile, as alternatives to FO in low fishmeal diets fed to rainbow trout (Oncorhynchus mykiss) and describes the subsequent effects on fish growth, fatty acid composition and health. Insect oil (IO), genetically modified canola oil (CO), palm oil (PO) and linseed oil (LO) were used for the formulation of three TOBs viz., TOB-1 (30%IO+36%CO + 34%LO), TOB-2 (40%PO + 20%CO + 40%LO) and TOB-3 (50%TOB-1 + 50%TOB-2). Formulas TOB-1 and TOB-2 considered the total fatty acid profile based upon the general FO fatty acid profile, published fatty acid research for rainbow trout, and the fatty acid requirements of rainbow trout. A low fishmeal based basal diet containing 44% crude protein was formulated, and FO, TOB-1, TOB-2 and TOB-3 were incorporated in the basal diet to prepare the experimental diet groups, Control, TOB-1, TOB-2 and TOB-3, respectively. All experimental diets were fed to triplicate groups of rainbow trout juveniles (initial weight 7.9 ± 0.02 g) for 9 weeks. Growth performance (final weight, percent weight gain and specific growth rate) in TOBs fed groups were equal to the FO-based control group. Fish fed the TOB-3 diet consumed more feed followed by the control and TOB-1 diet groups. Significantly lower feed intake was observed in the TOB-2 diet group. Feed conversion ratio and protein efficiency ratio were not significantly influenced by dietary oil sources. Fish fed the control diet showed significantly higher hepatic lipid content compared to TOB groups, followed by TOB-2, TOB-3, and TOB-1, which was significantly lower in hepatic lipid content. Muscle lipid content and whole-body major nutrient compositions were not significantly influenced by the dietary oil sources. Fatty acid composition of muscle and liver reflected that of the diets. Maximum values for n3 LC-PUFAs (EPA and DHA), lauric acid (C12:0) and C18:3n-3 were observed in the FO, TOB-1 and TOB-2 groups, respectively. Except for C12:0, muscle saturated fatty acid contents were significantly lower in TOBs-based diet compared to the FO-based control diet fish. As expected, muscle C12:0 content was significantly higher in the TOB-1 group followed by the TOB-3 group. TOB-2 and control groups had significantly lower content of C12:0. The fillet total n-3 LC-PUFA was significantly higher in fish fed the control diet group followed by TOB-3 and TOB-2 groups, TOB-1 showed significantly lower content of total n-3 LC- PUFA. Hepatic delta-5 desaturase (Δ5fad), delta-6 desaturase (Δ 6fad) and fatty acid elongase-2 (Elovl-2) gene expressions were significantly influenced by dietary oil sources, where TOB-based groups showed higher Δ6fad and Elovl-2 expressions. Measured innate immunity and antioxidant markers were not affected by TOBs. Finally, we concluded that TOBs could serve as a substitute for FO in rainbow trout feed without negatively impacting performance. Moreover, fillet total n-3 LC-PUFA of TOB-fed fish satisfies the suggested daily serving for humans.