Body Protein Content Research Articles

Effects of dietary fiber on growth, feed efficiency and nutrient utilization of tinfoil barb (Barbonymus schwanenfeldii, Bleeker 1853) fry

An 8-week feeding trial was conducted to determine dietary fiber utilization level in Barbonymus schwanenfeldii fry based on the growth, feed efficiency and nutrient utilization. Intestinal α-amylase activity and liver and intestinal histology were used to evaluate the growth performance of fish. Five isonitrogenous (48% crude protein) and isocaloric (20.1 kJ g⁻¹ gross energy) diets were prepared with different fiber levels (0.9%, 3.18%, 5.97%, 8.34% and 10.73%). Each diet was randomly assigned to triplicate groups of fish (0.557 ± 0.001 g) at 20 fry per 100 L glass aquarium. Results revealed that tinfoil barb fry tolerated 10.73% dietary fiber without compromising their growth. Average daily feed intake and feed conversion ratio linearly decreased with increasing fiber levels (P = 0.02). Protein efficiency had a positive association with dietary fiber levels (P = 0.03). Although whole body protein, ash and fiber contents were not related to dietary fiber levels, energy and lipid content linearly decreased with increased dietary fiber levels (P = 0.03). Retention of dietary protein and carbohydrate positively related to dietary fiber levels (P = 0.03). However, lipid and energy retentions were independent of dietary fiber concentrations. Intestinal α-amylase activity showed a unique association with dietary fiber intake in intestinal bulb (P < 0.0001) and hindgut (P = 0.01). However, irrespective of higher midgut amylase activity, its specific content was independent of dietary fiber levels. Besides, there were not any histopathological signs on the gut and liver of fish fed 0.9–10.73% dietary fiber. Meanwhile, condition factor and viscerosomatic index were independent of dietary fiber. Since feeding 10.73% dietary fiber did not affect the growth performance and nutrient utilization, it was concluded that B. schwanenfeldii fry could tolerate 10.73% crude fiber in their practical diet. However, future studies are warranted to determine maximum tolerability of fiber by the fish using further increase in dietary fiber level.

Regulatory mechanisms of nutrient metabolism and the impacts of iron and zinc nanoparticles on growth and physiology of Rohu, Labeo rohita

A 60-day feeding trial was done to investigate the effects of iron and zinc nanoparticles (Fe-NPs and Zn-NPs) on the growth and physiology of Rohu, Labeo rohita. The study aimed to determine the optimal levels of Fe-NPs and Zn-NPs that could improve the growth performance and nutrient metabolism of the fish. Five experimental diets containing varying levels of Fe-NPs and Zn-NPs (10–50 mg/kg) were fed to the fish, along with a control diet. The study found that weight gain, biomass, and specific growth rate increased significantly up to 30 mg/kg feed, and feed utilization was more efficient in the same group. Whole body protein and lipid content were also higher at 30 mg/kg NPs. However, the haematological, lipid, and enzymatic profiles showed varying dose-dependent responses to NPs concentrations. The accumulation rate was higher for Fe-NPs than Zn-NPs in the liver. Based on the analysis, a dietary NPs level of 29.49 mg/kg feed was optimal for Rohu. These findings could contribute to the knowledge of regulatory mechanisms of nutrient metabolism and support sustainable aquaculture practices. In conclusion, this study highlights the potential benefits of using Fe-NPs and Zn-NPs in fish diets, as they can improve growth performance and nutrient metabolism. However, the results also suggest that the optimal levels of Fe-NPs and Zn-NPs vary depending on the specific physiological parameters being measured. Further research is needed to explore the long-term effects of Fe-NPs and Zn-NPs on fish health and the environment.

The influence of supplementary feeding during suckling and later weaning on growth performance, incidences of post-weaning diarrhoea and immunity of piglets

There is an urgent call for alternative strategies to the use of antibiotics for treatment of diarrhoea during the first 14 days of the post-weaning period. The alternative strategies should be directed at enhancement of the robustness of pigs in terms of body weight at weaning, and contribute to proper functional development and maturation of the intestine before and after weaning. Therefore, both nutrition and physiological age are of high interest. We hypothesised that a liquid nutritional supplement during the suckling period, and/or an increased weaning age, would enhance growth performance of the piglets during the suckling and post-weaning period. A 2 × 2 factorial design with two nutritional strategies; i.e., supplementation with milk replacer/feed (milk replacer provided from day 2 shifted to wet feed at day 12 of age) vs. solely suckling of the sows; and two weaning ages (day 24 vs. day 35) were used. As expected, average weight at weaning and average daily gain after weaning were greater in litters weaned at day 35 (P < 0.001). During the first week after weaning, greater average daily gain (P < 0.001) was observed for litters supplied with milk replacer/wet feed, and greater feed intake (P < 0.001) was observed in piglets supplied with milk replacer/wet feed and weaned at day 35. Piglets weaned at day 35 had greater average body content of protein and fat (P < 0.001) as compared with their littermates weaned at day 24. Provision of the milk replacer/wet feed during suckling increased the faecal dry matter content (P = 0.05) after weaning; while the proportion of piglets with a faecal consistency score >3 was greatest in litters weaned at day 35 and raised solely on sow milk (P = 0.03). The results showed that the nutritional supplementation before weaning had beneficial impact on intestinal functionality (with regard to faecal dry matter content results), while increased weaning age improved growth performance before and after weaning, as well as increased fat depots after weaning. The provision of nutritional supplement and increased weaning age enhanced post-weaning feed intake. In conclusion, the applied management strategies (supplementary feeding during suckling and later weaning) improved piglets’ characteristics before and after weaning, indicating enhanced robustness among weaned piglets.

Reassessment of dietary protein and lipid requirements for large yellow croaker, Larimichthys crocea, reared in net pens

AbstractAt present, large yellow croaker, Larimichthys crocea, a carnivorous fish ranked fifth in aquaculture production among marine finfishes in the world, still relies on raw fish diet because formulated feed alone is not able to sustain rapid growth of the fish. The present study evaluated growth, feed utilization efficiency, body composition and antioxidant capacity of large yellow croaker fed diets containing four protein (430, 460, 490 and 520 g/kg) and three lipid (60, 90 and 120 g/kg) levels. Fish weighing 11.4 ± 2.8 g were fed with the test diets in net pens for 8 weeks. Final body weight and nitrogen retention efficiency (NRE) were dependent on dietary protein and lipid levels and their interaction. Weight gain, body protein content, serum catalase (CAT) activity and liver glutathione peroxidase (GSH‐Px) activity were dependent on dietary protein and lipid levels. Phosphorus retention efficiency was dependent on dietary protein level and interaction between protein and lipid levels. Hepatosomatic index, body lipid and energy contents, activities of superoxide dismutase (SOD) and GSH‐Px in serum, and CAT activity and malondialdehyde content in liver were dependent on dietary lipid level. The final body weight and weight gain of fish fed at 490 g/kg protein level did not significantly differ from those fed at 520 g/kg protein level. The final body weight, weight gain and NRE of fish fed at 90 g/kg lipid level were higher than those fed at 60 g/kg lipid level, but did not significantly differ from those fed at 120 g/kg lipid level. The maximum weight gain occurred in fish fed the diets either containing 520 g/kg protein or 90 g/kg lipid. The body lipid content, as well as SOD and GSH‐Px activities in serum, were higher in fish fed the diets with 90 and 120 g/kg lipid compared to fish fed the diets with 60 g/kg lipid. The present study reveals that the optimal dietary protein and lipid levels for large yellow croaker reared in net pens were 490–520 g/kg and 90 g/kg, respectively.

Punica granatum (Pomegranate) Peel Extract Pre-Treatment Alleviates Fenpropathrin-Induced Testicular Injury via Suppression of Oxidative Stress and Inflammation in Adult Male Rats.

Fenpropathrin (FNP) is one of the commonly used insecticides in agriculture and domestically, leading to environmental and health problems. The goal of the current investigation was to determine how well pomegranate peel extract (PGPE) could prevent the testicular toxicity and oxidative stress induced by FNP. Four groups of male Wistar rats were randomly assigned: negative control (corn oil), PGPE (500 mg/kg BW), positive control (FNP; 15 mg/kg BW, 1/15 LD50), and PGPE + FNP. For four weeks, the rats received their doses daily and orally via gavage. The major phytochemical components (total phenolic, flavonoids, and tannins contents) detected in PGPE by GC-MS included ellagic acid, hydroxymethylfurfurole, guanosine, and pyrogallol with high total phenolic, flavonoids, and tannin contents. FNP-treated rats showed a marked elevation in testicular levels of thiobarbituric acid-reactive substances, hydrogen peroxide, and protein carbonyl content, as well as the activity of aminotransferases and phosphatases. Meanwhile. a significant decline in body weight, gonadosomatic index, glutathione, protein contents, enzymatic antioxidants, and hydroxysteroid dehydrogenase (3β HSD, and 17β HSD) activity was observed. In addition, significant alterations in testicular P53, Cas-3, Bcl-2, IL-β, IL-10, testosterone, follicle-stimulating and luteinizing hormones, and sperm quality were detected. Furthermore, biochemical and molecular changes were corroborated testicular histological abnormalities. Moreover, PGPE-pretreated FNP-intoxicated rats demonstrated considerable improvement in the majority of the studied parameters, when compared to FNP-treated groups. Conclusively, PGPE provided a potent protective effect against the testicular toxicity caused by FNP, due to its antioxidant-active components.

On‐farm growth performance of different strains of tilapia, Oreochromis niloticus reared in earthen ponds

AbstractThe growth of aquaculture sector in Kenya has been anchored on farmed Nile tilapia Oreochromis niloticus. Different strains of the species exist in Kenya with unknown quality due to lack of stock improvement programmes coupled by variations in breeding and management practices in different hatcheries. The seeds supplied to farmers have not exhibited good performance and resilience to changing climate. There is need to validate the quality of strains supplied to fish farmers in Kenya. This study sought to compare the growth performance of three strains of farmed Nile tilapia; Sagana strain (SAG‐F8) produced through selective breeding, super YY strain (KAM‐YY) from Kamuthanga fish farm and the local strain (LOC‐T) obtained from Siaya County. The fish were stocked in fertilised earthen ponds measuring 300 m2 in triplicates at 3 fish/m2. The fish were fed on 35% crude protein diet for 180 days at Bukani Aquapark located in Busia County, Kenya. There was no significant difference in mean weight gain (MWG) between SAG‐F8 and LOC‐T strain exhibiting 159.786 ± 6.76 g and 158.623 ± 4.67 g, respectively. However, under similar conditions, the KAM‐YY strain had a significantly lower MWG (131.74 ± 4.75 g) compared to the two strains. Food conversion ratio (FCR), specific growth rate (SGR) did not demonstrate any significant difference among the different strains. The body protein content in the SAG‐F8 fish strain was higher (65.40 ± 0.20%) followed by LOC‐T strain (61.23 ± 2.34%) and lastly KAM‐YY strain had the lowest (60.37 ± 0.89%). In this study, the impact of genetic improvement has been demonstrated to influence growth and feed efficiency as well as body composition. These improved strains will substantially increase fish production and productivity, hence, a positive impact on the fish farmers' livelihoods when supplied to the farmers and seed multipliers.

Body and milk production traits as indicators of energy requirements and efficiency of purebred Holstein and 3-breed rotational crossbred cows from Viking Red, Montbéliarde, and Holstein sires

This study aimed to compare rotational 3-breed crossbred cows of Viking Red, Montbéliarde, and Holstein breeds with purebred Holstein cows for a range of body measurements, as well as different metrics of the cows' productivity and production efficiency. The study involved 791 cows (440 crossbreds and 351 purebreds), that were managed across 2 herds. Within each herd, crossbreds and purebreds were reared and milked together, fed the same diets, and managed as one group. The heart girth, height at withers, and body length were measured, and body condition score (BCS) was determined on all the cows on a single test day. The body weight (BW) of 225 cows were used to develop an equation to predict BW from body size traits, parity, and days in milk, which was then used to estimate the BW of all the cows. Equations from the literature were used to estimate body protein and lipid contents using the predicted BW and BCS. Evidence suggests that maintenance energy requirements may be closely related to body protein mass, and Holstein and crossbred cows may be different in body composition. Therefore, we computed the requirements of net energy for maintenance (NEM) on the basis either of the metabolic weight (NEM-MW: 0.418 MJ/kg of metabolic BW) or of the estimated body protein mass according to a coefficient (NEM-PM: 0.631 MJ/kg body protein mass) computed on the subset comprising the purebred Holstein. On the same day when body measurements were collected, individual test-day milk yield and fat and protein contents were retrieved once from the official Italian milk recording system, and milk was sampled to determine fresh cheese yield. Measures of NEM were used to scale the production traits. Statistical analyses of all variables included the fixed effects of herd, days in milk, parity, and genetic group (purebred Holstein and crossbred), and the herd × genetic group interaction. External validation of the equation predicting BW yielded a correlation coefficient of 0.94 and an average bias of -4.95 ± 36.81 kg. The crossbreds had similar predicted BW and NEM-MW compared with the Holsteins. However, NEM-PM of crossbreds was 3.8% lower than that of the Holsteins, due to their 11% greater BCS and different estimated body composition. The crossbred cows yielded 4.8% less milk and 3.4% less milk energy than the purebred Holsteins. However, the differences between genetic groups were no longer significant when the production traits were scaled on NEM-PM, suggesting that the crossbreds and purebreds have the same productive ability and efficiency per unit of body protein mass. In conclusion, measures of productivity and efficiency that combine the cows' production capability with traits related to body composition and the energy cost of production seem to be more effective criteria for comparing crossbred and purebred Holstein cows than just milk, fat, and protein yields.

Bacillus thuringiensis: a natural endophytic bacterium found in wild plants.

Despite the fact that Bacillus thuringiensis is the most widely used bacterium in biological pest control, its ecology has been notoriously neglected. Its role in nature is uncertain, and a defined habitat and niche are under discussion. In this report, wild-type strains were isolated from the inner plant tissues as natural endophytic bacteria in wild plants. Once a reliable superficial sterilization technique was standardized, leaf samples from 110 wildlife plant species within 52 families were processed to obtain their endophytic microflora, which were able to grow in artificial media. From 93 morphologically different isolates, 22 showed the typical sporangium morphology of B. thuringiensis (endospore and parasporal bodies). These isolates were identified and characterized by their 16S ribosomal RNA, hag gene, MLST, and cry gene sequences. Also, isolates were characterized by Bc-RepPCR and parasporal body protein content. All the isolates showed at least some of the typical B. thuringiensis features tested, but 10 showed information in all those features, which, in a rigorous selection, were taken as B. thuringiensis sensu stricto strains. Only three subspecies were identified: five kurstaki, four nigeriensis, and one thuringiensis. None showed toxicity against mosquito larvae or Caenorhabditis elegans, and only one showed significant toxicity against Manduca sexta larvae. The role of B. thuringiensis as a natural endophytic bacterium is discussed.

Coenzyme Q10 and N-acetyl cysteine modulates the haematological parameters, markers of oxidative stress and membrane bound phosphatase in spleen toxicity induced by aniline hydrochloride

Aniline is widely used chemical for industrial purpose. Exposure to aniline can lead to various health issues in human being. The most common toxic effect of aniline is splenotoxicity which is produced via the generation of oxidative stress. The present study examines the protective effect of coenzyme Q10 and N-acetyl cysteine on spleen weight, body weight, endogenous antioxidants and membrane bound ATPases in aniline hydrochloride (AH) induced spleen toxicity in rats. Adult male albino rats were divided into five groups, each group consists of six rats. Toxicity was induced by administration of AH (100 ppm, p. o) in drinking water for 30 days. Body weight, markers of oxidative stress and haematological parameters were assessed at the end of treatment period. Treatment rats received Coenzyme Q10 (CoQ10, 10 mg/kg/day/p.o) and N- acetyl cysteine (NAC, 300mg/kg/ day p.o) alone and in combination for 30. AH toxic rats showed a significant elevation of spleen weight, WBC count, iron content, LPO level, NO level and Ca ATPase whereas a significant decrease in body weight, haemoglobin, RBCs level, Protein content, GSH and Na/ K and Mg ATPase were observed. Administration of Coenzyme Q10 (CoQ10, 10 mg/kg/day/p.o) and N- acetyl cysteine (NAC, 300mg/kg/ day p.o) together for 30 consecutive days shows a significant decrease in spleen weight, WBC level, iron content, LPO level, NO level whereas significant increase in body weight, hemoglobin level, RBCs level Protein content, GSH level, Na/ K ATPase, Ca and Mg ATPase when compared with aniline treated group and CoQ10 or NAC alone treated groups. These findings indicate the synergistic &amp; protective effect of CoQ10 and NAC in aniline induced spleen toxicity in rats compared to alone antioxidants.

A forecast effects of climate change and anthropogenic compounds in Gambusia holbrooki: ecotoxicological effects of salinity and metformin

Due to global warming and extreme weather events, estuarine and coastal ecosystems are facing sudden fluctuations in salinity. These ecosystems are also threatened by organic and inorganic compounds that increase water pollution. Metformin is an antidiabetic drug commonly used by patients with type-2 diabetes, and an increase in environmental concentration has been recorded. To better understand the impacts of these two stressors on aquatic organisms, this study assessed: 1) the acute (96 h) ecotoxicological effects (antioxidant and biotransformation capacity, oxidative damage, energetic reserves, and protein content, neurotoxicity) induced by a range of metformin concentrations in Gambusia holbrooki under different salinities (17, 24, 31 expressed as Practical Salinity Units - PSU); and 2) the same endpoints after chronic exposure (28 d) under a range of metformin concentrations at a salinity of 17. The results obtained from the acute exposure showed interactions between salinity and metformin in G. holbrooki superoxide dismutase (SOD) activity, body protein, and glycogen (GLY) contents. The results revealed that an increase in salinity can modulate the response of G. holbrooki to metformin. Chronically exposed organisms showed that metformin led to a significant decrease in SOD activity at most of the tested concentrations (0.5, 1.0, and 10 µg/L). In addition, glutathione S-transferases increased and glutathione peroxidase activity decreased significantly at concentrations of metformin of 5 and 10 at the µg/L, respectively. Therefore, overall, metformin can lead to potential oxidative stress in G. holbrooki the highest metformin concentrations tested and the GLY content in G. holbrooki increased after exposure to metformin concentrations of 0.5, 1.0 and 5.0 μg/L. Published studies have already shown that metformin alone can lead to oxidative damage in aquatic species, endangering the biodiversity of aquatic ecosystems. Therefore, additional ecotoxicological studies should be performed to characterize if other metformin concentrations combined with salinity, or other climate change-related factors, might impact non-target species. Standard toxicity bioassays may not be predictive of actual pollutants (e.g. metformin) toxicity under variable environmental conditions, and the investigation of a wider range of exposure conditions could improve the accuracy of chemical risk assessments.

The influence of dietary protein concentration on digestive enzyme activities, growth, and body composition in juvenile bullseye snakehead (Channa marulius).

The bullseye snakehead (Channa marulius) is considered as an affordable and robust freshwater fish for farming in Asia. However, there is limited knowledge on the species' full nutritional requirements to date with extensive gaps in our knowledge and particularly in precision aspects of protein requirements. Therefore, a three-month feeding trial was conducted under semi-intensive farming conditions to determine the protein requirement of bullseye snakehead using test diets containing 40 (P40), 45 (P45), 50 (P50), and 55% (P55) crude protein levels. The growth performance results revealed that the 55% dietary protein group (P55) had the highest final mean weight (14.09 g fish-1), and net weight gain (12.82 g fish-1). When compared to other dietary treatments, the final weight (R2 = 0.921), and weight gain (R2 = 0.913), displayed a linear increasing trend as dietary protein is raised. The lowest FCR was observed in 50% (1.94±0.01) and 55% (1.97±0.01) CP diet groups compared to dietary treatments. Further analysis has shown that the body protein content also significantly increased as dietary protein was raised to 55%. Although, a reverse trend was found in body lipid levels with increasing protein in the diet. The incremental dietary protein also elevated proximal intestinal protease activity but decreased amylase and lipase activity. The overall essential and non-essential amino acids levels of snakehead fillet muscle reflected an increase in dietary protein. Overall, this study has shown that the fish fed a diet with 55% crude protein attained the highest growth performance and nutrient profile of the whole fish when compared to other dietary treatments tested. It would appear we did not obtain the maximum potential for growth under the present experimental conditions due to the upper protein constraint of 55% in the diet. Further quantitative studies are suggested.

Fresh Azolla, Azolla pinnata as a Complementary Feed for Oreochromis niloticus: Growth, Digestive Enzymes, Intestinal Morphology, Physiological Responses, and Flesh Quality.

Azolla is a potential fish feed ingredient due to its high nutritional value, abundant production, and low price. This study is aimed at evaluating the use of fresh green azolla (FGA) as a replacement ratio of the daily feed intake on the growth, digestive enzymes, hematobiochemical indices, antioxidant response, intestinal histology, body composition, and flesh quality of monosex Nile tilapia, Oreochromis niloticus (with an average initial weight of 108.0 ± 5.0 g). Five experimental groups were used and differed in commercial feed replacement rates of 0% (T 0), 10% (T 1), 20% (T 2), 30% (T 3), and 40% (T 4) with FGA for 70 days. Results showed that 20% replacement with azolla gave the highest values of growth performance and hematological parameters and the best feed conversion ratio, protein efficiency ratio, and fish whole body protein content. The highest levels of intestinal chymotrypsin, trypsin, lipase, and amylase were noted in 20% replacement with azolla. Fish fed diets with FGA levels of 10% and 40% showed the highest values for the thickness of the mucosa and submucosa layers among all treatments, respectively, while the length and width of the villi decreased significantly. No significant (P > 0.05) differences in the activities of serum alanine transaminase, aspartate transaminase, and creatinine were detected among treatments. The hepatic total antioxidant capacity and the activities of catalase and superoxide dismutase significantly (P < 0.05) increased while the activity of malonaldehyde decreased with increasing the replacement levels of FGA up to 20%. With increasing levels of dietary replacement with FGA, muscular pH, stored loss (%), and frozen leakage rate (%) were significantly decreased. Finally, it was concluded that the dietary replacement of 20% FGA or less may be considered a promising feeding protocol for monosex Nile tilapia, which may lead to high fish growth, quality, profitability, and sustainability for the tilapia production sector.

Effects of different pretreatments on the physiochemical properties of pig manure and its potential in promoting the growth and nutrient accumulation of black soldier fly larvae (BSFL)

An economic and feasible way to use black soldier fly larvae consists of treating livestock manure to convert it into high value-added protein feed. This study was aimed to investigate the effects of different pretreatments on the physiochemical properties of pig manure and the its potential in promoting the growth and nutrient accumulation of black soldier fly larvae (BSFL). Fresh pig manure was pretreated by aerobic fermentation (AE), anaerobic fermentation (AN) and high temperature anaerobic fermentation (HAN) for 2 or 5 days, and then inoculated with BSFL. Results indicate that EC value, DOC, DON, TN, NH₄⁺-N and protein content were the highest in HAN pretreated manure. The individual body weight and protein content of BSFL fed with HAN pretreated manure increased by 20% and 30%, respectively, compared with those fed with AE pretreated manure. In terms of performance, BSFL fed with HAN pretreated manure showed the highest waste reduction, bioconversion rate, waste conversion efficiency and protein conversion efficiency. The conclusion of the present study may be helpful for further research on the conversion of organic waste by BSFL.

Dietary Thymol Improved Growth, Body Composition, Digestive Enzyme Activities, Hematology, Immunity, Antioxidant Defense, and Resistance to Streptococcus iniae in the Rainbow Trout (Oncorhynchus mykiss).

In this study, thymol (TYM) at dietary levels of 0, 1, 1.5, 2, and 2.5 g/kg diet was used to evaluate its effects on growth, digestive performance, immunity, and resistances to the infection induced by Streptococcus iniae in the rainbow trout, Oncorhynchus mykiss. A number of 450 fish (35.8 ± 4.4 g; Mean ± SD) were distributed to 15 tanks (30 fish/tank) in three replicates and fed TYM for 60 days. After feeding period, Fish fed 1.5-2.5 g TYM showed better growth, higher digestive enzyme activity, and body protein content compared to other diets (P < 0.05). Regression analysis indicated a polynomial relationship between growth parameters and dietary TYM levels. Based upon the varied growth parameters, the optimum dietary TYM level was 1.89% for FCR. TYM at dietary levels of 1.5-2.5 g significantly enhanced liver antioxidant enzyme activity [superoxide dismutase (SOD), glutathione peroxidase (GPx), and catalase (CAT)], immune components in blood [alternative complement activity (C3), total immunoglobulin (Ig), lysozyme activity, bactericidal activity, and total protein], and in mucus [alkaline phosphatase (ALP), protease activity, lysozyme activity, bactericidal activity, and total protein] compared to other diets (P < 0.05). TYM at dietary levels of 2-2.5 g significantly decreased malondialdehyde (MDA) levels compared to other experimental groups (P < 0.05). In addition, use of TYM at dietary levels of 1.5-2.5 g upregulated the expression of the immune-related genes (C3, Lyz, and Ig) (P < 0.05). In contrast, the expression of inflammatory genes, tumor necrosis factor (TNF-α) and Interleukin-8 (IL-8) significantly were downregulated in response to 2-2.5 g TYM (P < 0.05). The hematology of the fish also altered in response to dietary TYM, where the values of corpuscular hemoglobin concentration (MCHC), hemoglobin (Hb), red blood cell (RBC), hematocrit (Hct), and white blood cell (WBC) significantly increased in fish fed 2-2.5 g TYM compared to other diets (P < 0.05). In addition, MCV significantly decreased in response to 2-2.5 g TYM (P < 0.05). After challenge with Streptococcus iniae, the survival rate was significantly higher in fish fed 2-2.5 g TYM compared to other diets (P < 0.05). The results of the present study concluded that TYM in the diet of rainbow trout can improve the fish growth and immunity and increase the resistance of the fish to Streptococcus iniae infection. The results of this study recommend an optimized dietary level of 2-2.5 g TYM for the fish.

Valorization of chicken intestine: A process of protein hydrolysate for fish feed attractant using pilot plant scale system

Chicken intestine as a poultry industry byproduct is rich in protein, contains various endogenous enzymes and can be prepared as a hydrolysate via autolysis. This research examined the physicochemical properties of chicken hydrolysate as a feed attractant. Growth of fish fed on the chicken hydrolysate-coated diet was compared with fish fed on a commercial hydrolysate (C). Three chicken hydrolysates were prepared at 60 °C for 4 h on a pilot plant scale including autolysis at pH 3 (S1), supplemental enzyme addition at pH 6.11 (S2) and a combination of supplemental enzyme addition following autolysis at pH 3 (S3). Highest yield was found in S2 (76%) followed by S3 (74%) and S1 (72%). The chicken hydrolysate had lower protein content (13–16%), higher fat (21–23%) and lower viscosity at 7429–10607 cP compared with C. Degrees of hydrolysis (DH) of S1, S2, S3 and C were 56%, 73%, 65% and 61%, respectively. Highest number of peptides less than 3 kDa associated with feed palatability was found in S2 (76%), followed by S3 (49%), C (29%) and S1 (28%). The three chicken hydrolysates were rich in essential amino acids similar to the C sample but with smaller amounts of amino acids in S1 and S3 due to the acidic pH preparation. An 8-week feeding trial of two selected fish species (hybrid catfish and Nile tilapia) was conducted in a water-recirculation system to investigate the effect of different hydrolysate-coated diets on fish growth performance. Highest body weight of hybrid catfish at 65.20 g gave weight gain of 150.15% and specific growth rate 1.73% d−1. Optimal feed conversion ratio (FCR) at 1.49 was observed in the S2 diet (p < 0.05). Improved growth performance was observed in Nile tilapia for diets coated with all chicken hydrolysates but no significant difference was found (p ≥ 0.05). Highest values of the hematological parameters, including hemoglobin, hematocrit and mean corpuscular hemoglobin concentration, were found in the two fish groups fed with S1, S2 and S3 diets (p < 0.05). At the end of the experiment, hybrid catfish and Nile tilapia fed with the S2 and S3 diets had the highest fish body protein content at 17% and 16%, respectively (p < 0.05). Our results showed that the three chicken hydrolysates, particularly S2, could potentially be used as feed attractants for freshwater fish.

Contribution of gut microbiomes and their metabolomes to the performance of Dorper and Tan sheep.

Livestock is an excellent source of high nutritional value protein for humans; breeding livestock is focused on improving meat productivity and quality. Dorper sheep is a distinguished breed with an excellent growth performance, while Tan sheep is a Chinese local breed famous for its delicious meat. Several studies have demonstrated that the composition of gut microbiome and metabolome modulate host phenotype. In the present study, we performed 16S amplicon sequencing and metabolomic analyses of the rumen and hindgut microbiome of 8-month-old Dorper and Tan sheep, raised under identical feeding and management conditions, to explore the potential effects of gut microbiome and its metabolites on growth performance and meat quality. Our study identified Lactobacillus, a marker genus in the rumen, to be significantly associated with the levels of fumaric acid, nicotinic acid, and 2-deoxyadenosine (P-value < 0.05). Statistical analysis showed that nicotinic acid was significantly negatively correlated with body weight (P-value < 0.01), while 2-deoxyadenosine was significantly positively correlated with fatty acids content (P-value < 0.05). There was a biologically significant negative correlation between Phascolarctobacterium and deoxycytidine levels in the hindgut. Deoxycytidine was significantly positively correlated with body weight, protein, and amino acid content. Differences in rumen fermentation patterns that are distinctive among breeds were identified. Tan sheep mainly used Lactobacillus and fumaric acid-mediated pyruvic acid for energy supply, while Dorper sheep utilize glycogenic amino acids. The difference of iron metabolism in the hindgut of Dorper sheep affects lipid production, while Phascolarctobacterium in Tan sheep is related to roughage tolerance. The accumulation of nucleosides promotes the growth performance of Dorper sheep. These findings provide insights into how the microbiome-metabolome-dependent mechanisms contribute to growth rate and fat contents in different breeds. This fundamental research is vital to identifying the dominant traits of breeds, improving growth rate and meat quality, and establishing principles for precision feeding.

Biochemical and molecular responses of the freshwater snail Pila sp. to environmental pollutants, abiotic, and biotic stressors

The semi-sessile, ectothermic, amphibious mollusc Pila globosa receives less attention for studying its environmental aspects. Its ecological role, ecotoxic and physiological responses to environmental factors including pollution and during dormant periods such as hibernation and estivation to understand key information about many cellular metabolic events need to be revealed. We reviewed the ecotoxic and physiological responses of P. globosa to various abiotic and biotic stressors such as heavy metals, organophosphorous, carbamate and butachlor in relation its adaptation to energy expenditure, fat metabolism in the dormant period, desiccation, etc. The responses analysed in terms of oxidative stress, respiratory and antioxidant enzymes, carbohydrate metabolism and activities of neurotransmitter enzymes such as acetylcholinesterase to better understand the connection between environmental factors and metabolic events in P. globosa. Articles published in the English language from 1952 to July of 2022 in PubMed, Google search engine and AGRICOLA that describes any of the above-mentioned search terms in P. globosa were included in the review article. Articles not containing any of the above terms were excluded. The 41 results were found in PubMed and 10 results from AGRICOLA and about 80 filtered articles from Google, totaling about 80 articles published until July 2022 were included in this review. The varied enzymatic activities observed in this organism under the exposure to various chemicals imply their possible use as biomarkers of eco-toxicological studies in freshwater and grassland ecosystems, for example, alleviated body carbohydrate and protein contents are up to 32% and 37% during aestivation and hibernation, respectively. Similarly, activities of enzymes such as adenosine monophosphate deaminase, adenosine deaminase, succinic dehydrogenase, cytochrome-c-oxidase, and glutamate dehydrogenase are downregulated by 75.5%, 62.6%, 54%, 59%, and 62%, respectively, during above inactive periods. Acetylcholinesterase enzyme is found to be the most susceptible enzyme to be downregulated by 225%, 130%, 64%, 198%, 96.08% in this snail under exposure to environmental pollutants such as phorate (30 mg/L), formothion (37.5 mg/L), trichlorfon (2.5 mg/L), aldicarb (120 mg/L) and butachlor (100 µ moles), respectively. In conclusion, P. globosa can serve as a reliable ectothermic model for comparative ecotoxicological studies in grassland and freshwater environmental monitoring.

Effects of dietary carbohydrate levels on growth, metabolic enzyme activities and oxidative status of hybrid snakehead (Channa maculata ♀ × Channa argus ♂)

An 8-week feeding trial was aimed to explore the effects of dietary carbohydrate on growth performance, metabolic enzyme activities and oxidative status of hybrid snakehead (Channa maculata ♀ × Channa argus ♂). A total of 540 healthy hybrid snakehead with initial body weight of (39.4 ± 0.01) g were selected and randomly divided into 18 cages, with 30 in each cage. Six isonitrogenous and isolipidic diets with different levels of digestible carbohydrate (α-starch) levels (DCL) (0%, 5%, 10%, 15%, 20% and 25%) were fed to hybrid snakehead. Results showed that dietary carbohydrate supplementation had significant effects on final body weight (FW), weight gain (WG), feed conversion ratio (FCR) and protein efficiency ratio (PER) of hybrid snakehead in a third order polynomial (cubic) model, with the optimal level established at 10.2%–12.0%. Effects on Condition factor (CF) of hybrid snakehead was described by a second order polynomial (quadratic) relationship. Hepatosomatic index (HSI) and viscerosomatic index (VSI) showed a linear relationship with increasing DCL. The body protein, crude lipid and hepatic glycogen content of hybrid snakehead increased with the levels of carbohydrate supplementation (P < 0.05). Dietary supplementation with carbohydrate significantly increased the levels of plasma cholesterol (CHOL), triglyceride (TG), high-density lipoprotein cholesterol (HDL-C) and low-density lipoprotein cholesterol (LDL-C) in hybrid snakehead (P < 0.05). The activities of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in both plasma and liver were significantly enhanced by the highest level of carbohydrate (P < 0.05). Furthermore, the levels of superoxide dismutase (SOD) and catalase (CAT) in liver increased firstly and then decreased with the increasing of DCL (P < 0.05). The expression levels of genes encoding SOD, glutathione peroxidase (GSH-PX), proinflammatory cytokines interleukin 1β (IL-1β) and interleukin 8 (IL-8) in liver showed significantly increasing trend when DCL increased from 0% to 15%, followed by significant decline when DCL exceeds 15% (P < 0.05). The malondialdehyde (MDA) contents in liver were not affected by DCL. Based on these results, the optimal level of dietary carbohydrate supplementation was estimated at approximately 11% for maximum growth and normal metabolism of hybrid snakehead.

Growth performance, haematological parameters and proximate composition of rainbow trout Oncorhynchus mykiss fed varying dietary levels of protein hydrolysate from heads of Penaeus monodon shrimp processing industry

Fish farming is a huge industry in Vietnam, but there is a shortage of protein supplements for fish diets. A potential great source of protein supplement is the co-products of shrimp processing. The present study aimed to investigate the growth performance and haematological parameters of rainbow trout Oncorhynchus mykiss juveniles fed diets containing four different concentrations of shrimp head protein hydrolysates (0% as the control, 1, 3 or 5% SHPH, four replicates per treatment). Rainbow trout juveniles were randomly distributed into 12 tanks at a density of 30 individuals/tank and were fed twice a day at 8:00 and 17:00 for 8 weeks. Mean weight gain (MWG), specific growth rate (SGR), feed conversion ratio (FCR), protein efficiency ratio (PER) and survival (SR) were calculated. Significant differences (p<0.05) in MWG, SGR, FCR, PER and SR were detected between treatments, with fish fed 5% SHPH performing the best. Mean white blood cells (WBC), red blood cells (RBC), hemoglobin content (Hb) and hematocrit (Hct) significantly increased as dietary protein hydrolysate increased in the diet. Protein and triglyceride concentrations in plasma were not significantly affected by dietary treatment (p > 0.05). Furthermore, muscle and whole body lipid contents were higher in fish fed 3% and 5% protein hydrolysate from shrimp heads than other groups, but muscle and body protein contents in the group fed 5% were higher than other groups. Results from the present study showed that protein hydrolysate from shrimp heads has good potential for use as protein supplement in rainbow trout diets up to 5%. Supplemental dietary protein hydrolysate from shrimp heads also has potential as an immune enhancer because of an increase in WBC. These data provide a potential use for a current waste product and might serve as a model for other countries that have both warm water crustacean industries and cold water fish industries. Further studies to explore the use of protein hydrolysate from shrimp heads in fish diets at more than 5% are recommended.

Effects of carbon-nitrogen ratio manipulation on the growth performance, body composition and immunity of stinging catfish Heteropneustes fossilis in a biofloc-based culture system

A 10-week indoor culture study was done to evaluate the effects of varying C/N ratios on growth performance, body composition, immunity, and haematology of stinging catfish Heteropneustes fossilis cultured in zero-water exchange culture tanks. Biofloc-based tanks with four levels of C/N ratio (12, 15, 18, 21) via the addition of carbohydrate referred to as ‘CN12′, ‘CN15', 'CN18' and 'CN21', and freshwater tanks operated with the facility of water exchange and without the addition of carbohydrate referred to as 'Control' (CN10). Fish (average weight 0.60 g) were stocked in 15 experimental tanks with 300 L water capacity and fed a commercial diet containing 30 % crude protein. The water quality parameters (pH, temperature, total ammonia nitrogen, nitrite nitrogen, dissolved oxygen, total suspended solids, and total dissolved solids) were monitored throughout the experiment. There was no significant (P > 0.05) difference among the treatments in the case of DO and temperature. The pH, total ammonia nitrogen, and nitrite nitrogen contents decreased with increasing C/N ratio, whereas the total dissolved solids and total suspended solids increased with gradually increasing the C/N ratio. Compared to the control, the treatment CN15 resulted in a 72 % and 34.4 % higher percent weight gain and specific growth rate, respectively. CN15 treatment resulted in improved feed utilization, as measured by feed conversion ratio (1.32 ± 0.07) and protein efficiency ratio (1.36 ± 0.10), which were 36.2 % lower and 54.5 % higher, respectively, than control. However, there were no differences in growth performance and feed utilization data between CN15 to CN21. Increasing the C/N ratio increased the body protein and ash contents and decreased the moisture and lipid contents compared to control. In the serum lysozyme test, the lysozyme value increased with a gradually increasing C/N ratio, and a better result was found in the CN15-CN21 treatments (15.58–15.74 µg ml−1) compared to the control (12.45 µg ml−1). At the end of the rearing period, fish were subjected to a challenge test with Aeromonas hydrophilla to determine the mortality rate where mortality was the lowest in CN15 treatment. Furthermore, increasing the C/N ratio from 15 to 21:1 showed better results for haemoglobin, white blood cells, red blood cells and hematocrit values. Overall, the manipulation of the C/N ratio from 15 to 21:1 revealed suitable for the feed utilization, growth performance, body composition, and immunity of stinging catfish. Therefore, maintaining a C/N ratio of 15:1 can be recommended for the culture of stinging catfish in the biofloc system.