Feeding Trial Research Articles

Effect of dietary replacement of fish meal by poultry by-product meal on the growth and hepatic health in loach (Paramisgurnus dabryanus)

Our objective was to systematically evaluate the impact of substituting fish meal (FM) with poultry by-product meal (PBM) in fish feed on the growth and hepatic health of loach. Six diets with different levels of PBM (0%-PBM0, 10%-PBM10, 30%-PBM30, 50%-PBM50, 70%-PBM70 and 90%-PBM90 were formulated. After 8 weeks feeding trial, the highest weight gain (WG) was observed in 55% PBM replacement ratio. Meanwhile, the lowest feed conversion ratio (FCR) were observed in 41.56% PBM replacement ratio. In addition, dietary PBM induced hepatic oxidative stress including increasing the activity of aminotransferase from PBM0 to PBM50 group, whereas the activity of those enzymes was decreased from PBM50 to PBM90 group. Meanwhile, histological analysis showed that the lipid vacuoles in the liver were increased from PBM0 to PBM50 group, then decreased from PBM50 to PBM90 group (P< 0.05). Moreover, primary bile acid biosynthesis was the only one pathway enriched in top 20 significant pathways by transcriptomic and metabolomic analysis. Specifically, the key bile acid synthesis gene CYP7a1 was down-regulated, while CYP7b1 evinced an up-regulated pattern in PBM50 group compared to PBM0 group. In short, the PBM replacement ratio of up to 50% in diets was appropriate for rearing loach, while higher PBM replacement ratio resulted in extremely oxidative stress in the liver.

Recovery of intestinal microbial community in Penaeus vannamei after florfenicol perturbation

The concept and application of probiotic intervention for restoring intestinal microbial dysbiosis induced by antibiotics in aquaculture are still in early stages. This study aimed to investigate potential responses of various recovery strategies, including natural recovery and probiotic intervention, in restoring the growth and intestinal microbial community of Penaeus vannamei following florfenicol perturbation. The basal diet (control, CN) was supplemented with florfenicol (FC) or Lactobacillus plantarum W2 (LM) throughout the entire feeding trial. Meanwhile, the basal diet was supplemented with florfenicol for 7 days, followed by a period without florfenicol (natural recovery, FB), or with live strain W2 (probiotic recovery, FM), for a duration of 35 days. Results indicated that dietary supplementation of strain W2, whether continuous or following florfenicol perturbation, along with continuous florfenicol supplementation, significantly enhanced the growth performance of shrimp. Early natural recovery and probiotic intervention did not induce significant alterations in microbial diversity and community structure. Florfenicol perturbation resulted in a decrease in the abundance of potentially beneficial bacteria in intestinal microbial community of shrimp. However, both probiotic intervention and natural recovery strategies gradually reduced the abundance of potentially pathogenic bacteria while increasing the abundance of potentially beneficial ones. The robustness of microbial network decreased during florfenicol perturbation, showed gradual improvement during probiotic recovery, and remained relatively low during natural recovery and continuous florfenicol supplementation. Moreover, the microbial community composition in intestinal habitat significantly differed under various recovery strategies compared to the control. Notably, the microbial community composition of intestinal habitat following probiotic recovery exhibited greater similarity to that of continuous strain W2 supplementation without florfenicol perturbation. In summary, dietary supplementation of florfenicol perturbed intestinal microbial community stability of shrimp, whereas probiotic intervention and natural recovery facilitated the attainment of new stable states by altering keystone taxa. Considering intestinal microbial community stability of shrimp, the recovery of microbial community through probiotic intervention appears to be more effective than natural recovery.

Positive effects of Lithospermum erythrorhizon extract added to high soybean meal diet on growth, intestinal antioxidant capacity, intestinal microbiota, and metabolism of pearl gentian grouper

This study aims to investigate the effects of adding 2‰ Lithospermum erythrorhizon (LE) extract to the high soybean meal diet on the growth, intestinal antioxidant capacity, intestinal microbes, and metabolism of pearl gentian grouper (Epinephelus fuscoguttatus ♀ × E. lanceolatus ♂). Three diets included FM, SBM, and SBMLE, in which FM was the whole fish meal diet, SBM was the soybean meal replacing 50% fish meal protein, and SBMLE was the SBM diet supplemented with 2‰ LE extract. After a 56-day feeding trial, the results showed the weight gain rate (WGR), specific growth rate (SGR), and feed efficiency rate (FER) of pearl gentian grouper in FM and SBMLE group was significantly higher than that of SBM (P < 0.05). Furthermore, high soybean meal dietary added LE extract inclusion significantly increased the SOD, CAT, and GSH-Px activity while significantly decreasing the MDA level (P < 0.05). Significant differences were in the gene expression of cytokines il1-β, il8, tnf-α, il10, and tgf-β between the SBMLE and SBM groups (P < 0.05). In addition, Microbiomics results revealed increased ASVs and alterations in gut microbiota composition, characterized by a decrease in Bacteroidota and an increase in Proteobacteria, Nautella, and lactococcus after adding LE extract. Furthermore, the substantial reduction in Firmicutes and Acidobacterota induced by high soybean meal feed was reversed by LE extract. Metabolic pathway enrichment analysis showed that LE extract mitigated soybean-induced enteritis (SBMIE) by affecting two critical metabolic pathways: arachidonic acid metabolism and histidine metabolism. In conclusion, adding LE extract to a high soybean meal diet can improve the growth performance and immunity of the pearl gentian grouper, and LE can play a mitigating role in SBMIE by regulating lipid metabolism, amino acid metabolism, and intestinal flora balance.

Effects of different feeding rates on growth performance, intestinal digestive enzyme activity, and intestinal microbial composition of red swamp crayfish (Procambarus clarkii)

The study aimed to investigate the effects of different feeding rates on the growth, muscle composition, intestinal digestive enzyme activities, and intestinal microbiota composition of juvenile crayfish (Procambarus clarkii). A total of 240 crayfish with an initial body weight of 8.33±0.50 g were randomly distributed into five groups, and each group had three replicates. The five groups corresponded to five different feeding rates of 2%, 4%, 6%, 8%, and 10% body weight per day (BW/day). The feeding trial lasted for six weeks. The results showed that the final body weight (FBW), weight gain rate (WGR), and specific growth rate (SGR) first increased when the feed rate increased from 2% to 6 % (P&lt;0.05) and then showed a decreased trend with the further increase of the feeding rate, but no significant differences were observed. The feed conversion ratio (FCR) increased with a rise in feeding rate, which reached a peak at the feeding rate of 10% (P&lt;0.05). The survival rate (SR), hepatosomatic index (HSI), and condition factor (CF) were unaffected by the feeding rates (P&gt;0.05). The moisture, crude protein, crude fat, and ash contents of crayfish muscle remained unchanged among all feeding rate groups. Intestinal activities of lipase and amylase increase with the feeding rate (up to 6%) increasing (P&lt;0.05). The ACE and Chao indices in the groups fed at 2% of feeding rate were significantly lower than those at a feeding rate of 10% (P&lt;0.05). The relative abundance of Firmicutes in the groups fed at feeding rates of 4%, 6%, and 8% was higher than that in other groups (P&lt;0.05), Citrobacter in the group fed at feeding rate of 6% was lower than that in different groups (P&lt;0.05). The intestinal microbiota primarily functions in connection to amino acid, carbohydrate, and vitamin metabolism. Therefore, the optimum feeding rate could be 6.0% of the feeding rate of juvenile P. clarkii.

Dietary energy level and β2-adrenergic agonist supplementation on growth performance, dietary energy, carcass traits, and visceral mass of hairy lambs

Context The beta-agonist zilpaterol (ZH) is a feed additive that improves growth performance via protein accretion during the finishing phase of ruminant fattening. However, evaluating the possible interaction between ZH and nutrients of the diet has received limited attention. Aims We investigated the changes in growth performance and carcass traits in response to ZH supplementation of hairy lambs fed finishing diets with different energy concentration. Methods Forty-eight Pelibuey × Katahdin crossbred male lambs (43.8 ± 6.3 kg) were used in a 34-day feeding trial to evaluate the interaction between diet energy density [8.37 (LE) and 8.79 (HE) MJ of net energy for maintenance (NEm) per kilogram of diet] and zilpaterol hydrochloride supplementation (ZH, dosed at 0 or 6 mg ZH/kg) on growth performance, carcass traits, and visceral mass. All diets contained 14.5% crude protein (CP). Key results There was no interaction of energy level and ZH in any of the variables evaluated. HE increased average daily gain (ADG) and gain efficiency (GF) without affecting the observed-to-expected dietary NE. Zilpaterol supplementation increased ADG, GF, and observed-to-expected dietary NE. Both HE and ZH increased carcass weight. HE increased carcass fat, whereas ZH decreased it. HE increased dressing percentage. ZH increased longissimus muscle area, the muscle:fat ratio in the shoulder, and leg whole-cut proportion. Visceral mass was not affected by energy level. ZH decreased visceral fat. Conclusions Increasing diet energy from 8.37 to 8.79 MJ NEm/kg enhanced growth performance and carcass traits but did not improve dietary energy utilization. Supplemental ZH enhanced growth performance, dietary-energy utilization and carcass traits of lambs. Implications ZH supplementation is a tool to enhance growth performance by improving protein accretion and reducing carcass fat. Response to ZH supplementation is independent of the differences in energy density of finishing diets.

Dietary intervention of propolis and/or turmeric boosted growth, hematology, biochemical profile, and antioxidant-immune responses and their associated gene expression in Nile tilapia (Oreochromis niloticus) challenged with Edwardsiella tarda

AbstractImmunostimulant phytogenic feed additives are given great concern for improving fish health, growth, immune responses, and resistance to diseases. This research investigated the impact of dietary propolis (PRO), turmeric (TUR), and their combination on the growth, hematology, antioxidant-immune responses, and their regulating genes in Nile tilapia (Oreochromis niloticus) during Edwardsiella tarda challenge. For 8 weeks, a total number of 320 fish (20.70 ± 0.14 g) were allocated into four groups at random, each with eight replicates (10 fish each). The first group (1st) was given the basal diet (control) without any supplements. The 2nd, 3rd, and 4th groups were supplemented with 1% PRO, 1% TUR, and the mixture (1%PRO + 1%TUR), respectively. The experimental groups were challenged intraperitoneally with E. tarda at a dose of 0.1 mL (1 × 105 CFU) at the termination of the feeding trial, and the fish survival was estimated for an additional 7 days. The results demonstrated that fish-fed diets supplemented with PRO and/or TUR showed higher body weight, condition factor, specific growth rate, feed intake, and feed efficiency utilization than the control group (P &lt; 0.05). The hematological, protein profile, and antioxidant-immune (total antioxidant capacity, lysozymes, and IgM) parameters were substantially improved in the challenged fish fed on PRO and/or TUR diets compared to the challenged non-fed fish. The lipid profile and malondialdehyde were substantially decreased in the challenged fish fed on PRO and/or TUR diets compared to the challenged non-fed group. Notably, a down-turning of nuclear factor kappa B (NFκB) and tumor necrosis factor-alpha (TNF-α) expression with up-turning of nuclear factor erythroid 2-related factor 2 (Nrf2) and transforming growth factor-beta (TGF-β) expression was noticed in the challenged fish fed on PRO and/or TUR diets compared to the challenged non-fed fish. Noteworthy, dietary PRO and/or TUR improved the fish survival during E. tarda challenge. The mixture of PRO and TUR can be added to Nile tilapia diets to enhance their growth, immune response, and resistance to E. tarda. These outcomes help in the sustainable development of the Nile tilapia culture industry. Graphical Abstract

Growth, immunomodulatory, histopathological, and antibacterial effects of phytobiotic-incorporated diets on Oreochromis niloticus in unchanged water

Phytobiotics are promising diet alternatives, yet their effectiveness in high-risk aquaculture conditions remains underexplored. Therefore, a 90-day feeding trial was conducted based on dietary supplementation of Nile tilapia, Oreochromis niloticus, with herbal extracts, namely, lemon balm [Melissa officinalis (MOE)], marjoram [Origanum majorana (OME)], and chamomile [Matricaria chamomilla (MCE)] with 0% water change. The treated groups were compared to groups untreated with herbs or control groups [positive control (PC; 0% water change) and negative control (NC; 20% water exchange per day]. Fish were cultured at stocking density (20 fish m-3: 1.8kg of biomass/m3). We conducted a physicochemical analysis of the water and the clinical responses, growth, and immune responses of the fish were evaluated. Furthermore, the herbal-supplemented fish were then challenged with a pathogenic Edwardseilla tarda strain and mortality was monitored. In the 1st and 2nd months, the water parameters were within the permissible limits. After that, a fatally low dissolved oxygen concentration and the highest levels of ammonia, nitrite, nitrate, and pH were recorded during the 3rd month. Blood and immune assays were conducted in the treated groups and control groups. The herbal-treated groups appeared healthy, but during the 3rd month, lethargy and decreased appetite were evident. Generally, the herbal-treated fish showed improved growth performance parameters, survival rates, and resistance against pathogenic bacteria E. tarda, particularly in the OME and MOE-treated groups compared to the positive control group. Finally, phytobiotic supplements were shown to improve fish stress tolerance and immune activation for a certain period under stressful conditions or unchanged water, based on the stocking density, dosages of herbs used, and the extent of deterioration of the water quality.

Assessing functional properties of diet protein hydrolysate and oil from fish waste on canine immune parameters, cardiac biomarkers, and fecal microbiota

Locally produced fish hydrolysate and oil from the agrifood sector comprises a sustainable solution both to the problem of fish waste disposal and to the petfood sector with potential benefits for the animal’s health. This study evaluated the effects of the dietary replacement of mainly imported shrimp hydrolysate (5%) and salmon oil (3%; control diet) with locally produced fish hydrolysate (5%) and oil (3.2%) obtained from fish waste (experimental diet) on systemic inflammation markers, adipokines levels, cardiac function and fecal microbiota of adult dogs. Samples and measurements were taken from a feeding trial conducted according to a crossover design with two diets (control and experimental diets), six adult Beagle dogs per diet and two periods of 6 weeks each. The experimental diet, with higher docosahexaenoic (DHA) and eicosapentaenoic (EPA) acids contents, decreased plasmatic triglycerides and the activity of angiotensin converting enzyme, also tending to decrease total cholesterol. No effects of diet were observed on serum levels of the pro-inflammatory cytokines interleukin (IL)-1β, IL-8, and IL-12/IL-23 p40, and of the serum levels of the anti-inflammatory adipokine adiponectin. Blood pressure, heart rate and echocardiographic measurements were similar between diets with the only exception of left atrial to aorta diameter ratio that was higher in dogs fed the experimental diet, but without clinical relevance. Diet did not significantly affect fecal immunoglobulin A concentration. Regarding fecal microbiome, Megasphaera was the most abundant genus, followed by Bifidobacterium, Fusobacterium, and Prevotella, being the relative abundances of Fusobacterium and Ileibacterium genera positively affected by the experimental diet. Overall, results from the performed short term trial suggest that shrimp hydrolysate and salmon oil can be replaced by protein hydrolysate and oil from fish by-products without affecting systemic inflammatory markers, cardiac structure and function, but potentially benefiting bacterial genera associated with healthy microbiome. Considering the high DHA and EPA contents and the antioxidant properties of fish oil and hydrolysate, it would be worthwhile in the future to assess their long-term effects on inflammatory markers and their role in spontaneous canine cardiac diseases and to perform metabolomic and metagenomics analysis to elucidate the relevance of microbiota changes in the gut.

Effect of dietary Anabaena supplementation on nutrient utilization, metabolism and oxidative stress response in Catla catla fingerlings

A 60-day feeding trial was conducted to evaluate the effects of dietary Anabaena blue-green algae (ABGA) meal on the growth performance, digestibility, and physio-metabolic responses of Catla catla fingerlings (initial average weight 9.45 ± 0.15 g). Six iso-nitrogenous (30% crude protein) and iso-caloric (378.09 Kcal. digestible energy/100 g) diets were formulated: a control diet (A0, 0% ABGA) and five experimental diets with varying ABGA inclusion levels (A3: 3%, A6: 6%, A9: 9%, A12: 12%, A15: 15%). The results demonstrated that there were no significant differences (P > 0.05) in percentage weight gain (PWG), specific growth rate (SGR), protein efficiency ratio (PER), and feed conversion ratio (FCR) among the experimental groups. Additionally, dietary ABGA did not significantly affect (P > 0.05) body carcass composition among different groups. However, amylase activity significantly decreased (P < 0.05) in the A12 and A15 fed groups, whereas lipase and protease activities remained insignificant (P > 0.05) across all groups. Notably, oxidative stress responses (SOD; superoxide dismutase and CAT; catalase), carbohydrate metabolic enzymes (LDH; lactate dehydrogenase and MDH; malate dehydrogenase), and serum glucose levels increased significantly (P < 0.05) with higher ABGA inclusion. Conversely, serum albumin content significantly decreased (P < 0.05) in the ABGA-fed groups. There were no significant differences (P > 0.05) observed in serum total protein, albumin/globulin (A/G) ratio, aspartate aminotransferase (AST), and alanine aminotransferase (ALT) activities among the experimental groups. Hematological parameters revealed that RBC (red blood cell) count, hemoglobin (Hb) concentration, and packed cell volume (PCV) significantly decreased (P < 0.05), while WBC (white blood cell) count significantly (P < 0.05) increased with higher dietary ABGA inclusion. In conclusion, the inclusion of dietary ABGA up to 15% did not impair nutrient utilization and supported normal growth performance in C. catla fingerlings. However, higher inclusion levels may have a detrimental effect on their growth, nutrient utilization, and physio-metabolic responses.

Dietary glycine supplementation enhances creatine availability in tissues of pigs with intrauterine growth restriction.

This study tested the hypothesis that dietary supplementation with glycine (Gly) enhances the synthesis and availability of creatine (Cr) in tissues of pigs with intrauterine growth restriction (IUGR). At weaning (21 d of age), IUGR pigs and litter mates with normal birth weights (NBW) were assigned randomly to one of two groups, namely, supplementation with 1% Gly or 1.19% L-alanine (isonitrogenous control) to a corn- and soybean meal-based diet. Blood, kidneys, liver, pancreas, jejunum, longissimus lumborum muscle (LLM), and gastrocnemius muscle (GM) were obtained from the pigs within 1wk after the feeding trial ended at 188 d of age to determine concentrations of guanidinoacetate (GAA), Cr, creatinine, and phosphocreatine (CrP). The organs were also analyzed for activities and mRNA levels for Cr-synthetic enzymes: L-arginine:glycine amidinotransferase (AGAT; forming GAA from Gly and L-arginine) and guanidinoacetate N-methyltransferase (GAMT; converting GAA and L-methionine into Cr). AGAT activity was present in the kidneys, liver, and pancreas, whereas GAMT activity was found in all the organs analyzed. AGAT and GAMT were most active per g of tissue in the kidneys and liver, respectively. Based on tissue mass, the kidneys had the greatest (P < 0.001) AGAT activity per whole organ, followed by the liver, while skeletal muscle had the greatest (P < 0.001) GAMT activity per whole organ, followed by the liver. Thus, the kidneys played a dominant role in forming GAA, whereas skeletal muscle and liver were the major sites for converting GAA into Cr. Dietary supplementation with 1% Gly enhanced AGAT activity in the kidneys and pancreas but reduced GAMT activity in the pancreas and small intestine, therefore directing GAA to the liver and skeletal muscle for Cr production. IUGR selectively reduced the concentration of Cr in LLM among all the organs studied. Except for the GM that had greater mRNA levels for GAMT in IUGR pigs, neither Gly nor IUGR affected mRNA levels for the selected genes in the tissues examined. Collectively, these novel results indicate that dietary Gly intake upregulates the Cr-synthetic pathway in swine.

Effects of Oxidized Soybean Meal and Oxidized Soybean Oil on the Muscle Oxidative Stability, Flesh Quality, Amino Acid Profile, and Fatty Acid Profile of Megalobrama amblycephala

This study aimed to investigate the effects of oxidized soybean meal and oxidized soybean oil on the muscle oxidative stability, flesh quality, amino acid profile, and fatty acid profile of blunt snout bream Megalobrama amblycephala. Oxidized soybean meal and oxidized soybean oil were obtained from fresh soybean meal (FSM) and fresh soybean oil (FSO) by heating. In the experimental diet, the proportions of oxidized soybean meal (OSM) and oxidized soybean oil (OSO) were 30% and 4.19%, respectively. The feeding trial was conducted for 8 weeks. The findings revealed that both OSM and OSO reduced glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), catalase (CAT), hardness, chewiness, and oxymyoglobin (OxyMb) and elevated the content of malondialdehyde (MDA), protein carbonyl (PC), and metmyoglobin (MetMb) in the muscle. OSM notably decreased the content of muscle essential amino acids (EAAs), nonessential amino acids (NEAAs), delicious amino acids (DAAs), and total amino acids (TAAs) compared with CON and OSO. Compared with CON and OSM, OSO significantly reduced the content of elaidic acid (C18:1n9t), linoelaidic acid (C18:2n6c), polyunsaturated fatty acids (PUFAs), ω-6 PUFAs, and the ratio of ω-6/ω-3, while stearic acid (C18:0), γ-linolenic acid (C18:3n6) and saturated fatty acids (SFAs) were significantly elevated. In conclusion, this study demonstrated that both OSM and OSO negatively impacted muscle antioxidant capacity and flesh quality. Moreover, OSM adversely affected the amino acid profile of the muscle, while OSO impaired the fatty acid profile.

Effects of Dietary Fiber and Copper on the Performance and Gut Microbiota of Finishing Pigs

This study aimed to investigate the effects of dietary fiber (DF) levels and copper concentrations on the production performance and cecal microbial diversity of finishing pigs. A 2 × 2 factorial experimental design was used, with different levels of dietary fiber (low [23% DF]: L and high [30% DF]: H) and copper concentrations (normal [25 mg/kg]: N and supplemented [45 mg/kg]: S) resulting in four diets (LN, LS, HN, and HS). Forty-eight hybrid barrows (Duroc × Landrace × Yorkshire), with an initial body weight of 76 kg ± 1.5 kg, were randomly assigned to four groups: LN, LS, HN, and HS, with 12 replicates per group and one pig per replicate. There was a 7-day adaptation period followed by a 56-day feeding trial, after which all pigs were slaughtered for sampling. Results indicated that in finishing pigs, the low dietary fiber group exhibited a higher final weight, a higher average daily gain, and a lower feed-to-gain ratio compared to the high fiber group (p &lt; 0.05). The LS group showed higher digestibility of dry matter, crude protein, crude fiber, ash, neutral detergent fiber, and DF than the HN and HS groups (p &lt; 0.05). Blood total protein levels were higher in the high fiber group, whereas blood Cu levels were higher in the supplemented copper group (p &lt; 0.05). High dietary fiber increased the activities of colonic carboxymethylcellulase and β-glucanase (p &lt; 0.05). Concentrations of acetic acid, propionic acid, and total volatile fatty acids were elevated in the high fiber group (p &lt; 0.05). Microbial α-diversity indices (observed species, Chao 1, and Shannon indices) increased with fiber but decreased with copper supplementation (p &lt; 0.05). The Firmicutes/Bacteroidetes ratio increased with fiber levels, with a higher relative abundance of Lactobacillus in the LS group. In conclusion, appropriate copper supplementation in diets can mitigate the negative effects of high fiber levels on finishing pig production performance by enhancing nutrient digestibility, fiber-degrading enzyme activity, regulating the microbial community, and its metabolic products.

Effects of fish meal replacement with composite proteins source on growth performance, antioxidant capacity and swim bladder quality of chu’s croaker (Nibea coibor)

Collagen, as a commercial functional protein, is widely applied in food, cosmetics, biomedicine and other industries, and swim bladder is regarded as an ideal source of raw materials due to its rich collagen content. Chu’s croaker (Nibea coibor), as an economical fish that can produce high-grade swim bladder, is popularly farmed, however, its high fishmeal demand limits the development of the feed industry. Therefore, it is worth thinking about how to reduce the use of fish meal without affecting the swim bladder quality. Given that, an 8-week feeding trial was conducted to investigate the effects of fish meal partially replaced (0.0%, 5.0%, 10.0%, 15.0%, 20.0%) with composite proteins (CPs, consisted of corn protein meal and hydrolyzed feather meal) on growth, antioxidant capacity and swim bladder quality (texture and collagen deposition) of chu’s croaker. Results showed that although growth performance decrease with the increase of CPs’ replacement level, it did not compromise the swim bladder quality. Specifically, 5% - 10% CPs did not affect the growth significantly, but can improve antioxidant capacity, protein content, collagen synthesis and texture quality of swim bladder. The enhancement of swim bladder texture, including hardness, chewiness, springiness, and adhesiveness may be caused by changes in the expression of related genes, such as colga1t1, col12a1, cyp27a1, etc. These results indicated that appropriate fish meal replaced by CPs could be applied during aquaculture practice after comprehensive consideration of feed cost, growth rate and quality of swim bladder. This study provides support for the development of cost-effective feed formulations that improve the sustainability and economic viability of chu’s croaker culture.

Impact of Providing Cowpea (Vigna unguiculata) Hay, Wheat Bran, and Their Mixes on Begait Lambs' Skin and Leather Quality

Aims: To evaluate the impact of adding wheat bran (WB), cowpea hay (CPH), or mixes of the two on the chemical and physico-mechanical properties of leather. To determine the ideal ratio for supplementing wheat bran and cowpea hay on the chemical and physico-mechanical properties of leather. Study Design: The study employed a randomized complete block design (RCBD) with five treatments and blocks. Place and Duration of Study: Northern Ethiopia, Humera Agricultural Research Center farm, starting from December 2016 until November 2017. Methodology: 25 intact male Begait lambs were bought from the local market, weighing an average of 28.02 ± 1.49 kg (mean ± SD) at 5 to 6 months of age. Based on their starting body weight, they were split into five groups and assigned randomly to each of the five treatments. The standard diet for T1, T2, T3, T4, and T5 consisted of giving natural grass hay ad libitum plus supplements of 300 g CPH, 225 g CPH + 75 g WB, 150 g CPH + 150 g WB, 75 g CPH + 225 g WB, and 300 g WB DM day-1. Three lambs per treatment were randomly chosen, slaughtered, and dressed down using standard commercial techniques at the end of the feeding trial to assess the quality of skin and leather. Results: Compared to the other treatment groups, the Begait lambs in T2 and T3 exhibited increased tensile strength, elongation strength, and thickness. However, the chemical makeup of skin was comparable between treatment groups. Conclusion: Therefore, this study concluded that all test diets generated skin and leather that largely complied with the chemical and physico-mechanical quality standards demanded by the leather industry.

Effects of Replacing Fish Meal with Rubber Seed Cake on Growth, Digestive, Antioxidant and Protein Metabolism of Juvenile Asian Red-Tailed Catfish (Hemibagrus wyckioides).

An 8-week feeding trial was conducted to assess the impact of replacing fish meal (FM) with rubber seed cake (RSC) on growth performance, digestive enzyme activity of the gut, antioxidant capacity and protein metabolism-related parameters of plasma and liver in juvenile Asian red-tailed catfish (Hemibagrus wyckioides) with an average body weight of 3.21 g. Four isonitrogenous (41.08 ± 0.17) and isolipidic (10.07 ± 0.11) diets were formulated, incorporating RSC at a level of 0%, 15%, 30%, and 45% (w/w) to progressively replace FM. Dietary inclusion of 15-30% RSC did not significantly affect growth performance (p > 0.05). However, the replacement of FM with RSC resulted in linear reductions in intestinal trypsin and amylase activities, with a significant reduction in intestinal amylase activity observed at the 45% RSC inclusion level. Dietary inclusion of 30-45% RSC decreased plasma glutamate dehydrogenase and aspartate aminotransferase activities, but increased plasma adenosine monophosphate deaminase and hepatic γ-glutamyltransferase activities. This may indicate that the high substitution of FM by RSC may affect the homeostasis of amino acid metabolism. Dietary inclusion of 15% RSC did not affect serum and hepatic antioxidant enzyme activities; however, dietary inclusion of 45% RSC significantly increased plasma malondialdehyde level, but decreased catalase activity. Furthermore, dietary inclusion of 30-45% RSC significantly increased hepatic lactate dehydrogenase activity. These results demonstrated that replacing a portion of FM with RSC is feasible, and dietary inclusion of 15% RSC did not have significant adverse effects on growth performance, digestive function and antioxidant capacity of H. wyckioides.

Make it a standard? The creation and variability assessment of a consensus standard protocol for Tenebrio molitor larvae feeding trials

Abstract Interest in the nutrition of the yellow mealworm (Tenebrio molitor L.) larvae is on the rise, leading to an increase in publications on this topic. The absence of a standard protocol and resulting differences in experimental designs reduces comparability among studies and impedes research on mealworm nutrition. To address this, a consensus standardised protocol was developed specifically for the evaluation of mealworm larval growth and performance in feeding trials. The efficacy of this protocol was evaluated through an international ring test involving seven partners using two wheat brans as dry feed (a standard bran and a local bran) at 27 °C and 60% relative humidity. As experimental units, plastic crates filled with 2.1 kg of bran and 10,000 4-week-old larvae were used with six replicates. Agar gel was provided as wet feed ad libitum. The mean individual larval weight and the number of larvae per crate were determined weekly until either three or more replicates ran out of feed or pupation exceeded 10%. At harvest, the total larval fresh biomass and amount of frass was determined. Larval samples were taken for chemical analysis. To assess the protocol, the within (repeatability) and between (reproducibility) laboratory variability was calculated for each parameter. The repeatability was good (limit at 12% (standard) and 14% (local)). The reproducibility was poorer with a limit 2.7 times higher for the standard feed (36%) and 3.8 times higher for the local feed (55%). For both feeds, the total larval fresh harvest, amount of frass and the larval protein concentration were the most consistent both within and among laboratories. The highest variability was observed at the early life stages and for the larvae ash content. The detailed consensus standard protocol and repeatability/reproducibility estimates can be used as basis for future mealworm feeding trials, comparing results and future improvements.

Impacts of alfalfa nutrient concentrate on pellet physical attributes, growth performance, metabolism and nutritional quality of rainbow trout, Oncorhynchus mykiss

This study addresses the escalating demand for aquatic feed by exploring the potential of alfalfa nutrient concentrate (ANC) as feed ingredient for rainbow trout. Test diets contained varying ANC levels (0%, 5%, 10%, 15%, and 20%) to replace fishmeal (32% in the 0% ANC diet) to achieve equal digestible protein and were processed using a cooking extrusion method. Analysis of feed pellets showed that pellet density increased with ANC levels (P < 0.001), resulting in sinking pellets at 20% ANC. Water stability and durability were improved while oil leakage decreased with increasing ANC levels (P < 0.05). Two feeding trials were conducted to test the diets in flow-through water systems with three replicates per diet. The first 10-week trial evaluated their impact on feeding, fecal physical quality, and the apparent digestibility coefficient (ADC) of dietary nutrients in rainbow trout (initial body weight , 18.0 ± 0.2 g). ANC inclusion did not impact the palatability and satiety feed intake of the fish (P > 0.05). However, the ADC of dry matter and phosphorus significantly decreased in fish fed the 20% ANC diet (P < 0.05). The second 9-week trial investigated the growth performance, nutrition quality, and metabolism of rainbow trout (initial body weight, 19.0 ± 0.2 g). While all fish exhibited substantial growth, fish fed diets with 10% to 20% ANC displayed lower specific growth rate and higher feed conversion ratio compared to those fed with 0% or 5% ANC (P < 0.05). The whole body protein content was higher in fish fed 5% ANC compared to all other treatments (P = 0.030). The biochemical parameters of plasma were similar across treatments, except for a decrease in plasma phosphorus levels in fish fed a 10% ANC diet compared to those fed a 0% ANC diet. (P = 0.033). Significant changes were observed in liver metabolism including tricarboxylic acid cycle, amino acid and energy metabolism pathways in fish fed the 20% ANC diet versus the 0% ANC diet (P < 0.05). These results demonstrate that ANC inclusion improved pellet physical quality without impairing feeding behavior and nutritional quality of the fish but inclusion ≥10% in the diet reduced fish growth. This study offers the first comprehensive assessment of the potential of ANC used in fish feed involving feed management, feeding evaluation, and the biological response.

Bacillus amyloliquefaciens SS1-fermented soybean meal influenced the flesh texture of Nile tilapia: Involvement of microbial metabolite propionate

Microbial fermentation is recognized to improve feed utilization and health of farmed animals. However, its effect on flesh quality and the underlying mechanisms remain understudied. Herein, Bacillus amyloliquefaciens SS1, a probiotic strain isolated from the intestinal tract of Nile tilapia (Oreochromis niloticus) was used to ferment soybean meal (FSM). Two tilapia experimental diets containing FSM and raw soybean meal were formulated for an eight-week feeding trial. Results showed that dietary FSM significantly increased the carcass ratio of fish, while there was no significant difference in weight gain or feed utilization between the two dietary treatments. Texture profile analysis showed that muscle springiness was improved by the FSM diet. There was no discernible difference in myofiber morphology between the two treatments. However, the FSM-fed fish had significantly lower muscle lipid contents than the control, accompanied by suppressed lipogenesis, while lipolysis was promoted both in muscle and liver tissues. Interestingly, the FSM diet modified gut microbial community, resulting in increased propionate concentrations. By establishing a high-fat model using primary hepatocytes of tilapia, we demonstrated the role of propionate in reducing lipid accumulation. Our finding highlights the emerging roles of gut-derived metabolites in affecting flesh quality by modifying host metabolism, providing a foundation for improving the flesh quality of aquaculture fish starting from the feed.

Nutritional composition of black soldier fly (Hermetia ilucens) larvae reared on vegetable wastes: effects on growth of village chickens

Context Black soldier fly larvae are a promising alternative ingredient in poultry feed. They might be able to replace soybean and fishmeal because the have high concentrations of protein and fat, and are also rich in vitamins and minerals, and because partial replacement of soybean and total replacement of fishmeal produce no adverse effect on the growth performance of village chickens. Therefore, they are a suitable replacement for these traditional ingredients in poultry feed. Aims This study determines the nutritive values of black soldier fly larvae and evaluates the effects of feeding diets containing black soldier fly larvae on the growth performance of village chickens. Methods Samples of black soldier fly larvae were subjected to proximate analysis before a total of 280 1-day-old village chicks were randomly divided into four groups. All groups were fed a basal diet with partial replacements of corn and soybean with black soldier fly larvae at 0% (Control), 5% (T1), 10% (T2) and 15% (T3) for 70 days. Each treatment group consisted of seven replicates, with 10 birds per replicate. The bodyweights, bodyweight gains and feed conversion rates were determined. Key results Dry rendered black soldier fly larvae contained 773.0 ± 0.08 g/kg dry matter, 36.1 ± 0.09 g/kg ash, 408.8 ± 0.28 g/kg crude protein, 283.0 ± 0.16 g/kg ether extract and 40.9 ± 0.44 g/kg crude fibre. The larvae also contained 2.041 MJ/kg of metabolisable energy, 20.4 g/kg of calcium and adequate concentrations of vitamins. The feeding trial showed an average bodyweight gain of 1231.45 ± 23.37 g and feed conversion ratio of 2.03 ± 0.15, which were most efficient with Diet T3. Conclusions Inclusion of 15% black soldier fly larvae in diets can enhance the growth performance of village chickens without adverse effects. Implications Partial replacement of soybean and total replacement of fishmeal in the diet of chickens by black soldier fly larvae are not affecting the growth performance of village chickens but might reduce the feed cost.

Condensed tannins from black wattle as a promising nutritional additive for Nile tilapia: growth, immune and antioxidant responses, and gut morphology

The present study aimed to investigate the potential of condensed tannins (CT), derived from black wattle (Acacia mearnsii) tree bark, as a nutritional additive for Nile tilapia (Oreochromis niloticus) juveniles. CT are known for their antioxidant and immune-modulating properties, and their inclusion in aquafeeds may enhance fish health and performance. In this study, six diets were formulated: one control diet (Con) with no additives, and five experimental diets supplemented with CT extract at concentrations of 150, 250, 500, 750, and 1000mg/kg (CT150, CT250, CT500, CT750, CT1000, respectively). The selection of these doses was based on previous studies indicating that lower concentrations (below 1000mg/kg of diet) of tannins may offer benefits, while higher concentrations could exhibit antinutritional effects. After a 90-day feeding trial, fish fed the CT150 diet exhibited significantly higher growth compared to the control group. Additionally, fish in the CT150 group showed higher plasma lysozyme activity, while myeloperoxidase activity and hemolytic activity of the complement system were significantly higher in all tannin-fed groups compared to the control. Notably, CT150-fed fish demonstrated liver antioxidant responses comparable to or better than the control group, with no significant increase in lipid peroxidation, suggesting antioxidant protection. Histological analysis revealed a significant increase in intestinal villi density in the CT150 and CT500 groups compared to the control. While all groups showed an increase in absorption surface area (ASA), this increase was statistically significant only in the CT250, CT500, and CT750 groups when compared to the control. Furthermore, the CT150 diet led to the highest survival rate (80%) following a bacterial challenge. These findings suggest that dietary supplementation with 150mg/kg of CT from black wattle bark provides the most beneficial effects on growth, immune response, and survival in Nile tilapia juveniles.