Effect of Harim-CLH, a chicken liver hydrolysate, as an enhancer of diet-palatability in Anguilla japonica culture

This study aimed to assess the effect of pyridoxine supplementation in the mandarin fish diet on growth performance, protein and lipid metabolism, and liver and intestinal histology. Mandarin fish were fed six diets with different levels of pyridoxine (2.67 mg/kg (control), 4.41 mg/kg, 6.57 mg/kg, 10.25 mg/kg, 17.93 mg/kg, 33.12 mg/kg diet) for 8 weeks, and samples were collected for analysis. The findings demonstrated that feeding mandarin fish a diet with 6.57 mg/kg pyridoxine led to a significant increase in weight gain rate (WGR), protein efficiency ratio (PER), whole-body crude protein, whole-body crude lipid, serum protein, cholesterol (CHO), triacylglycerol (TG), high-density lipoprotein-cholesterol (HDL-C), low-density lipoprotein-cholesterol (LDL-C), and alkaline phosphatase (ALP), as well as significantly lower serum glucose (GLU) and feed conversion ratio (FCR), compared to the control group (P < 0.05). Furthermore, we found a significant upregulation of the relative expression of genes associated with hepatic lipid oxidation and synthesis (hl, lpl, pparα, cpt1, cs, srebp1, and fas) and proteolysis (ast, alt, and gdh) in fish fed a diet containing 6.57 mg/kg pyridoxine (P < 0.05). Regarding the histological analysis, we observed a notable decrease in the quantity of intestinal mucus-secreting cells when the fish fed a diet containing 10.25 mg/kg pyridoxine (P < 0.05). These findings suggest that dietary pyridoxine supplementation promotes mandarin fish growth by improving the efficiency of protein and lipid utilization. Additionally, we used a broken-line regression analysis to estimate the optimal dietary pyridoxine requirement for mandarin fish in the range of 6.17-6.41 mg/kg based on WGR, FCR, and PER.

The present study was aimed at evaluating the effects of the feed additive curcumin on the growth and non-specific immune responses in juvenile Wuchang bream (Megalobrama amblycephala). Six experimental diets were formulated to contain graded curcumin levels (0, 15, 30, 60, 120 and 240 mg/kg of diet, respectively). After 60 days feeding trial, fish fed the 60 mg/kg curcumin diet had significantly higher weight gain rate (WGR) and specific growth rate (SGR), and significantly lower feed conversion ratio (FCR) than the control group. The number of leucocytes (WBC), interleukin-1 beta (IL-1β), tumor necrosis factor-α (TNF-α), alternative pathway of complement (ACH50), and respiratory burst activity increased with increasing dietary curcumin levels up to 60 mg/kg, and thereafter declined. Significantly lower alanine transaminase (ALT) and aspartate transaminase (AST) activities were observed in fish fed the 60 mg/kg curcumin diet compared to those in the control group. Fish fed with the diets containing 60 and 120 mg/kg curcumin had significantly higher TNF-α and ACH50 activities than those in the control, and the fish fed diets supplemented with 60 and 240 mg/kg curcumin had significantly higher IL-1β activities than those in the control. The results suggest that appropriate dietary curcumin supplementation (60 mg/kg curcumin of diet) significantly improved growth and non-specific immune responses in juvenile M. amblycephala.

The effects of different levels of dietary fermented plant-based protein concentrate on growth, hematology and non-specific immune responses in juvenile olive flounder, Paralichthys olivaceus

The utilization potential of soybean meal as an alternative protein source for fish meal in practical diets for the juvenile Japanese flounder (Paralichthys olivaceus) was assessed in the present study. Four isonitrogenous and isolipidic diets were formulated to contain 47% protein and 9% lipid. The animal-plant protein ratios (A/P ratio) in the diets,representing 4∶1(D1),3∶1(D2),2∶1(D3) and 1∶1(D4),respectively,were calculated by adjustment of supplementing proportion of fish meal (FM) and soybean meal (SBM). Two hundred and forty Japanese flounder with an initial average body weight of (13.22± 0.02) g were randomly assigned into twelve 900-liter tanks equipped with a flow-through seawater system. Each diet was randomly allocated to triplicate groups of twenty fish each. The fish were fed the test diets twice a day at a daily feeding rate of 2%-3% body weight for 56 days. At the end of the feeding trial,the fish were weighed by batch for the determination of weight gain rate (WGR),feed conversion ratio (FCR) and protein efficiency ratio (PER),and then five fish from each tank were randomly sampled and pooled by tank for the analysis of proximate composition in the whole body. Another five fish from each tank were randomly selected to collect serum and liver samples for the analysis of blood urea nitrogen (BUN),glutamic-pyruvic transaminase (GPT),glutamic-oxalacetic transaminase (GOT),free fatty acids (FFA),total protein (TP),triglyceride (TG),cholesterol (CHO),high-density lipoprotein cholesterol (HDL-C),and low-density lipoprotein cholesterol (LDL-C). WGR,PER,and SGR of Japanese flounder decreased,while FCR increased with increasing SBM ratio in diets,and significant differences for the parameters were found when SBM ratio in diets increased to upon 24% (P0.05); HSI followed the same pattern as WGR,and the values in D1 group were significantly lower than those of other groups (P0.05). The values of CF were not different among dietary treatments (P0.05). There were no significant differences in whole body moisture,crude protein,and ash content of the fish among dietary treatments,however,crude lipid content decreased as SBM ratio increased,and the values of D3 and D4 groups were significantly lower than that of D1 group. There was a tendency of marginal increased BUN content in serum and TP content in liver of the Japanese flounder with increased SBM ratio in diets,whereas the opposite trend is true for GOT,GPT activity in serum,and FFA conten in liver (P0.05);TP and HDL-C content in serum (P0.05). Serum TG and liver TG content increased significantly while the A/P ratio decreased to below 2∶1 (P0.05); serum CHO,serum LDL -C and liver CHO content of D1 group were significantly lower than those of other groups (P0.05). These results indicate that higher ratio replacement FM by SBM (D3 and D4) in diets could adversely affect the growth and protein and lipid metabolism of Japanese flounder,and the optimal SBM ratio in diets was 16% based on the results of growth performance,body composition,protein and fat metabolism indices,and cost of weight gain in the present study.

The Chinese soft-shelled turtle (Pelodiscus sinensis) has become increasingly susceptible to frequent diseases with the intensification of farming, which severely impacts the development of the aquaculture industry. Sodium butyrate (SB) is widely used as a feed additive due to its promotion of growth, enhancement of immune function, and antioxidative properties. This study aimed to investigate the effects of dietary SB on the growth performance, immune function, and intestinal microflora of Chinese soft-shelled turtles. A total of 300 Chinese soft-shelled turtles (mean weight: 11.36 ± 0.21g) were randomly divided into four groups with three parallel sets in each group. Each group was fed a diet supplemented with 0%, 0.005%, 0.01%, or 0.02% SB for 60 days. The results demonstrated an upward trend in weight gain rate (WGR) and specific growth rate (SGR) with increasing SB supplementation, and the experimental group fed with 0.02% SB showed a significant increase in WGR and SGR compared to other groups (P< 0.05). These levels of SB also decreased the levels of feed conversion ratio (FCR) and the total cholesterol (TC) content of Chinese soft-shelled turtles, and the 0.02% SB was significantly lower than that of other groups (P< 0.05). The activity of complement protein in vivo increased with increases in SB content, and the activities of complement C3 and C4 reached the highest level with 0.02% SB. The species abundance of the experimental group D fed with 0.02% SB was significantly higher than that of other groups (P< 0.05). Furthermore, the relative abundance of Clostridium sensu stricto 1 was significantly increased with 0.02% SB (P< 0.05). In conclusion, adding 0.02% SB to the diet improves the growth performance, feed digestion ability, and intestinal microbiota of Chinese soft-shelled turtles.

SUMMARYThe intensive finishing of steers on simple rations of 10% sorghum stubble and 90% sorghum grain plus urea was investigated. Fine grinding of the grain resulted in a lower mean daily intake, but a significantly greater efficiency of conversion of feed to carcass weight gain (P &lt; 0·01) than coarse grinding the grain. Coarse chaffing of the stubble significantly reduced the intake of the stubble in comparison with hammer milling, but had no significant effect on rate of body weight gain, total feed intake or efficiency of feed conversion.The addition to the ration of either 1 mg of selenium, or 200 mg vitamin E, 200 mg vitamin E and 100 mg vitamin K per day had no significant effect on rate or efficiency of body or carcass weight gain. Seven out of 32 steers which were not injected with 3 million i.u. of vitamin A at the start of the experiment exhibited nyctalopia. None of the 32 steers which received the vitamin A injection had hepatic vitamin A concentrations less than 33 μg/g. Vitamin A injection did not have a significant effect on the rate of body weight gain (mean ±S.E. 1·3 ± 0·03 kg per day), efficiency of feed conversion (10·4 ± 0·16 kg D.M. per kg carcass weight gain), or time to attain slaughter weight (133 ± 3 days). Drenching twice with thiabendazole had no significant effect on rate of body weight gain.

Evaluation of fish meal analogue as partial fish meal replacement in the diet of growing Japanese eel Anguilla japonica

This study investigated the effects of n-3 high unsaturated fatty acid (n-3HUFA) levels on the growth performance, antioxidant enzyme activities and fatty acid profiles of both subadult and adult Litopenaeus vannamei (L. vannamei). Seven iso-nitrogenous and iso-lipidic diets were used, containing n-3HUFA concentrations of 1.6 (control), 4.8, 7.4, 13.9, 23.9, 29.2 and 34.4 g/kg, respectively. Two 8-week feeding trials were conducted to determine the dietary n-3HUFA requirements of L. vannamei with an initial body weight of 4.25 ± 0.00 g (subadults) and 8.50 ± 0.01 g (adults). The results showed that the dietary n-3HUFA level significantly affected the weight gain rate (WGR), specific growth rate, the feed conversion ratio and the hepatosomatic index (HSI) (p < 0.05), but did not significantly affect the survival rate (p > 0.05). At appropriate level, dietary n-3HUFA improved growth performance and HSI of both subadult and adult L. vannamei. Both subadults and adults showed significant differences in body composition (p < 0.05), except for moisture and crude ash (p > 0.05). Cholesterol and low-density lipoprotein significantly decreased with increasing dietary n-3HUFA both in subadults and adults (p < 0.05); however, triglyceride showed no significant change (p > 0.05). High-density lipoprotein (HDL) in subadults was significantly affected by dietary n-3HUFA (p < 0.05), but followed no apparent regularity; HDL significantly changed in adults and showed an upward trend followed by a downward trend (p < 0.05). There was no significant effect on aspartate transaminase (AST) activity in subadults, but AST in adults and alanine transaminase (ALT) in subadults and adults were significantly affected (p < 0.05). Dietary n-3HUFA significantly affected serum polyphend oxidase, malic dehydrogenase, alkaline phosphatase, superoxide dismutase and sodium-potassium adenosine triphosphatase enzyme activities in gills (p < 0.05). The fatty acid composition of the shrimp tissue was associated with the fatty acid composition of the diet. Dietary n-3HUFA supplementation significantly improved the contents of tissue ∑HUFA and n-3HUFA, increased the n-3/n-6 ratio in the tail muscle and decreased the contents of tissue polyunsaturated fatty acid and saturated fatty acid (p < 0.05). Based on the WGR, the broken-line equations indicated that the optimum requirements of dietary n-3HUFA were determined to be 9.0 and 5.1 g/kg for subadult and adult L. vannamei, respectively.

The effects of various feeding ratios on the growth, body composition, and blood chemistry of the juvenile mandarin fish Siniperca scherzeri (initial body weight 9.6 g) were examined in recirculating freshwater system equipped with 21, 300 L tanks at 20 fish per tank. The triplicate groups of seven feeding ratios treatments were prepared: 100% (control), 95%, 90%, 85%, 80%, 75%, and 70% of satiation. The feed amount of control group was determined by supplying with apparent satiation and then the feed amounts of the other six feeding groups were determined based on the feed amount of the control group. Fish were hand-fed with test diet (55.4% crude protein) for 10 weeks. Weight gain (WG) and specific growth rate of fish fed to 100% satiation were not significantly (p &gt; 0.05) different from those of fish fed to ≥ 80% satiation but were significantly higher than those of fish fed to 75% and 70% satiation. Feed efficiency, protein efficiency ratio, and protein retention of 100% satiation were not significantly different from those of 95% and 90% satiation but were significantly (p &lt;0.05) lower than ≤ 85% satiation. Condition factor, hepatosomatic index, and coefficient variation were not significantly (p &gt; 0.05) affected by feeding ratio. Whole body composition and contents of hematocrit, glutamic oxaloacetic transaminase, glutamic pyruvic transaminase, glucose, total protein, and high-density lipoprotein cholesterol in blood serum were not significantly (p &gt; 0.05) affected by the feeding ratio; however, content of total cholesterol tended to decrease as the feeding ratio decreased. Using broken-line analysis of WG, it was suggested that the optimum feeding ratio of juvenile mandarin fish, ranging from 9.0 g to 37.0 g, appeared to be 87.7% of satiation without growth inhibition.

Management factors affecting mortality, feed intake and feed conversion ratio of grow-finishing pigs

The influence of various feeding patterns of emodin on growth, non-specific immune responses, and disease resistance to Aeromonas hydrophila in juvenile Wuchang bream (Megalobrama amblycephala)

This study was conducted to investigate the effects of dietary supplementation with tributyrin (TB) on the growth, serum biochemistry, antioxidant capability and intestinal morphology and structure of golden pompano (Trachinotus ovatus). Golden pompano was fed a diet containing four levels of TB (0%, 0.1%, 0.2% and 0.4%) for 56 days. The results showed that compared with the group without TB supplementation (the control group), with the addition of 0.2% and 0.4% TB, the final body weight (FBW) and weight gain rate (WGR) were significantly upregulated (p < 0.05), the specific growth rate (SGR) and feed conversion ratio (FCR) were significantly upregulated and downregulated respectively, with 0.2% TB addition (p < 0.05). In addition, serum levels of alkaline phosphatase (AKP), total antioxidant capacity (T-AOC) and total superoxide dismutase (T-SOD) were significantly increased, whereas the levels of aspartate transaminase (AST) and alanine transaminase (ALT), malondialdehyde (MDA) were significantly decreased with the addition of 0.1%, 0.2% and 0.4% TB (p < 0.05). Glutathione peroxidase (GPx) was significantly increased with 0.2% TB (p < 0.05), and glutathione (GSH) was significantly increased with 0.2% and 0.4% TB (p < 0.05). In the liver, T-AOC, T-SOD, GPx and GSH were all significantly upregulated, whereas MDA was significantly downregulated by the addition of 0.1%, 0.2% and 0.4% TB (p < 0.05). Moreover, the villus height was significantly increased by the addition of 0.1%, 0.2% and 0.4% in the anterior and posterior intestine (p < 0.05), whereas the villus width was significantly increased by the addition TB level at 0.1% and 0.2% in the anterior intestine and significantly increased only in the posterior intestine with 0.2% TB (p < 0.05). These data suggest that dietary TB can improve serum biochemistry, antioxidant capability, intestinal morphology and structure of golden pompano. However, dietary TB supplementation did not alter the whole-body composition (crude protein, moisture, ash and crude lipid), total protein (TP), albumin (ALB), total cholesterol (T-CHO), high-density lipoprotein cholesterol (HDL-C), globulin (GLB), triglyceride (TRIG), low-density lipoprotein cholesterol (LDL-C) in the serum and catalase (CAT) in the serum and liver. Moreover, based on the growth performance (WGR) and antioxidant related (MDA) indices in the serum and liver, the appropriate supplementation level of TB in golden pompano was estimated to be 0.25%, 0.29% and 0.32% using quadratic regression analysis respectively.

Ammonia is a key risk factor in intensive aquaculture systems. This experiment is aimed at investigating the influence of dietary protein levels on genetically improved farmed tilapia (GIFT, Oreochromis niloticus) under chronic ammonia stress. GIFT juveniles of 4.00 ± 0.55 g were exposed to high ammonia level at 0.88 mg/L and fed with six diets comprising graded protein levels at 22.64%, 27.26%, 31.04%, 35.63%, 38.47%, and 42.66% for 8 weeks. The fish in negative control was fed the diet with 31.04% protein in normal water (0.02 mg ammonia/L water). Our results showed that high ammonia exposure (0.88 mg/L) caused significant decrease in fish growth performance, hematological parameters, liver antioxidant enzymes (catalase and glutathione peroxidase), and gill Na+- and K+-dependent adenosine triphosphatase (Na+/K+-ATP) activity. When fish were under high ammonia exposure, the weight gain rate, special growth rate, feed efficiency, and survival rate elevated significantly with dietary protein supplementation increase to 35.63%, whereas protein efficiency ratio, hepatosomatic index, and viscerosomatic index showed a decreased tendency. Dietary protein administration significantly enhanced crude protein but reduced crude lipid contents in the whole fish. Fish fed diets with 35.63%-42.66% protein had higher red blood cell counts and hematocrit percentage than fish fed 22.64% protein diet. The values of serum biochemical indices (lactate dehydrogenase, aspartate aminotransferase, and alanine aminotransferase), hepatic antioxidant enzymes (superoxide dismutase, catalase, and glutathione peroxidase), and gill Na+/K+-ATP activity were all elevated with the increment of dietary protein. Moreover, histological analysis indicated that dietary protein administration could prevent the ammonia-induced damages in fish gill, kidney, and liver tissues. Based on weight gain rate as a response criterion, the optimal dietary protein requirement for GIFT juveniles under chronic ammonia stress was 37.9%.

The aim of the present study was a preliminary experiment on marine culture of Asian sea bass in the shrimp earthen ponds of Gwadar region (a region located in the coastal area of Oman Sea, southeastern of Iran). To this end, Asian sea bass frys reared for 7 months including 1 month nursery and 6 months growth-period. During the culturing periods, fish were fed ad libitum by commercial rainbow trout diets based on fish growth stages. After nursery period, the average weight (AW) of 11.05 ± 1.5 g and survival per cent of 65% obtained for fish. During the growth-out period, the AW increased continually from 31.4 ± 4.7 g in late June to 252.1 ± 30 g at the end of growth-out period in late December. Also, the highest values of monthly weight gain yielded during August, September and October when fish had the AW range of (76.9 ± 14.4) – (188.1 ± 12.8) g. The values of monthly feed conversion ratio (FCR) were low and similar from July to October and then increased in November and December. The values of total monthly feed intake (FI) increased continually from July to October and then with a decrease in November, increased again in December. The values of survival per cent after nursery and growth-out period were 65% and 66%, respectively. Also, the average of monthly FCR, FCR at the time of fish harvesting, total FI and total harvested biomass were 1.36, 2.5, 630.5 kg and 325 kg.

Selenium is an essential micronutrient in aquaculture, with its efficacy and safety strongly dependent on the chemical form used for supplementation. In this study, we systematically compared the effects of three selenium sources—sodium selenite (SS), selenium-enriched Bacillus licheniformis fermentation broth (BlSe), and selenium-enriched Saccharomyces cerevisiae fermentation broth (ScSe)—on the growth performance and physiological parameters of largemouth bass (Micropterus salmoides). The SS group exhibited a survival rate of 90%, whereas both the BlSe and ScSe groups achieved 100% survival. Compared with the control, the ScSe group showed a significant increase in weight gain rate. In contrast, the BlSe group displayed markedly reduced serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), and alkaline phospholipase (ALP). All selenium-supplemented groups demonstrated substantially enhanced muscle selenium content—by 326% (SS), 455% (BlSe), and 88% (ScSe)—together with elevated activities of hepatic glutathione peroxidase (GSH-Px) and total superoxide dismutase (T-SOD), and reduced malondialdehyde (MDA) content. Intestinal microbiota analysis revealed a shift from Firmicutes dominance (50%) in the control to Proteobacteria dominance (60%) across all treatment groups at the phylum level. At the genus level, Mycoplasma was predominant in the control and BlSe groups (~20% abundance), while Sphingomonas and Chloroplast were enriched in the SS and ScSe groups, respectively. Moreover, KEGG pathway analysis indicated upregulation of taurine and hypotaurine metabolism, biosynthesis of unsaturated fatty acids, and fatty acid biosynthesis in all selenium-treated groups. These findings underscore the potential of B. licheniformis-derived nano-selenium as a highly effective selenium source for sustainable aquaculture.