Optimum Dietary Level Research Articles

Effects of gingko, Ginkgo biloba extract on metabolic hormones, liver histology, and growth parameters of rainbow trout, Oncorhynchus mykiss exposed to diazinon

The medicinal plant, Ginkgo biloba (GB) has been used for centuries in traditional medicine to improve health in human. In this study, we investigated for the first time the protective effects of GB against the toxic effects of the organophosphate pesticide (PC), diazinon on metabolic hormones, plasma glucose, liver histology and growth parameters of rainbow trout, Oncorhynchus mykiss. In non-diazinon-exposed fish, groups supplemented with 1 and 2 g GB/kg diet showed higher levels of plasma thyroid hormones [(Triiodothyronine (T3) and thyroxine (T4)], body weight index (BWI %) and specific growth rate (SGR %) compared to control (non-GB-supplemented fish) (p < .05). The supplementation of fish with 4 g GB/kg diet decreased the BWI %, SGR %, and plasma thyroid hormones (p < .05). FCR values significantly decreased in fish supplemented with 1 and 2 g GB/kg diet (p < .05). Also, no alternations were found in plasma levels of cortisol and glucose and liver histology during 60 d experiment (p > .05). In diazinon-exposed fish, thyroid hormones, BWI %, and SGR % significantly decreased during exposure period in all experimental groups (p < .05). FCR values significantly increased in control and fish supplemented with 0.5 and 4 g GB/kg diet (p < .05). No significant changes were observed in FCR values of fish fed 1 and 2 g GB/kg diet (p > .05). The cortisol levels significantly elevated during exposure period in control and groups fed 0.5, 1, and 4 g GB/kg diet, while this hormone remained unchanged in fish supplemented with 2 g GB/kg diet (p > .05). The plasma levels of glucose significantly elevated in fish supplemented with 2 g GB/kg diet (p < .5). Based on histological observations, the severity of liver damages was lower in GB-supplemented fish compared to non-supplemented ones (p < .5). The lowest liver lesions were observed in fish supplemented with 1 and 2 g GB/kg diet (p < .5). In conclusion, the findings of this study showed that GB at optimum dietary levels (1–2 g GB/kg diet) could stimulate the growth and also moderate the growth suppressing effects, stress, and liver tissue damages induced by diazinon.

Could fructan sources in strawberry matrix be more effective as a tool for improvement of bone structure than these compounds added to diet alone? - Study on osteopenic rat model.

Osteoporosis, a disease associated with ovarian hormone deficiency following menopause, is the most common cause of age-related bone loss. Although an optimal intake of Ca is vital - both bone accretion during growth and maintenance in adult life - a great percentage of the population consumes far below the recommended amounts of this mineral. On the other hand, there are evidences that fructans enhance not only Ca absorption, but bone calcium as well. In the knowledge that estrogen deficiency and insufficient Ca in the diet during postmenopause cause serious problems with resultant osteoporosis, the aim of this study is to assess the effects of a diet enriched in fructan-containing sources alone, or in the "strawberry matrix", on the structure of bone in OVX rats under calcium hypoalimentation. Experimental animals were female Wistar rats, sham-operated or ovariectomized. The treatment with Ca-restricted diets also contained one of the sources of fructan (Jerusalem artichoke, yacon, Beneo Orafti Synergy1), in the amount providing 8% of fructans. Femur architecture of rats was assessed by tomography and Ca content by the AAS method. Ovariectomy led to a significant decrease in femoral Ca content, total mineral content and bone density of rats. This study shows that a diet containing inulin-type fructan (especially as a component of strawberry product) improved bone quality (i.e. increase in Ca content in femur, total density in middle part of bone, as well as decrease of endosteal circumference) in OVX rats under calcium hypoalimentation. These findings suggest that a fructan-enriched diet could be potentially useful for postmenopausal osteoporosis. It is important to determine an optimal dietary level of fructan with the long-term goal of developing a dietary strategy in osteoporosis prevention.

Effects of copper levels in diets high in plant ingredients on gilthead sea bream (Sparus aurata) fingerlings

Fish meal is increasingly substituted in diets for gilthead sea bream with ingredients of terrestrial origin which may affect the mineral content and availability. Among these minerals, copper (Cu) is an essential trace element whose excess may have a potential toxic effect. Since ingredients of terrestrial origin have higher Cu levels than marine ones it is important to define the optimal dietary supply of Cu. Therefore, the aim of this study was to evaluate optimal dietary inclusion level of Cu in low FM-FO diets for gilthead sea bream fingerlings.Five practical diets with low FM (10%) and FO (6%) contents were respectively supplemented with 5 levels of CuSO4 to provide 5.5, 7.4, 9.3, 11.0 and 32.0 mg Cu kg−1 diet. Sea bream fingerlings (12.6 ± 1.4 g, mean ± SD) were distributed in 15 tanks with 30 fish per tank in triplicates and randomly assigned one of the dietary treatments. The fish were fed three times a day until apparent visual satiation for 42 days. Growth was recorded at the end of the trial and samples were taken for biochemical, mineral, histology, X-ray and hepatic gene expression analyses.The results obtained suggest that gilthead sea bream fed practical diets based on plant protein sources that provide at least 5.5 mg Cu kg−1 need no additional Cu supplementation, whereas dietary contents of 11–32 mg Cu kg−1 negatively affected gilthead sea bream performance by reducing growth, increasing oxidative risk and inducing hepatic damage and cholestasis.Dietary Cu levels did not affect body weight, SGR, TGC or FCR, denoting that the level in the non-supplemented diet (5.5 mg Cu kg−1) was enough to cover the requirements for growth. However, increasing dietary Cu levels from 5.5 to 9.3 mg/kg-1 up-regulated cat gene expression. On the contrary elevation of dietary Cu levels up to 11.0 and 32.0 mg Cu kg−1 tended to reduce growth and increased liver steatosis, broken cell margin, peripheral nuclei and sinusoid dilatation which are the markers of hepatic damage and cholestasis denoting potential toxic effects of Cu.

The influence of dietary protein and energy levels on the performance, meat bone ratio and meat chemical composition of SenSi-1 Agrinak chicken

&lt;p class="Default"&gt;&lt;span lang="EN-US"&gt;Sensi-1 Agrinak is a strain of the improved native chickens for meat production in Indonesia. The objective of &lt;/span&gt;&lt;span lang="IN"&gt;this&lt;/span&gt;&lt;span lang="EN-US"&gt; study was to investigate influence of different dietary energy and protein levels on &lt;/span&gt;&lt;span lang="IN"&gt;p&lt;/span&gt;&lt;span lang="EN-US"&gt;erformance, meat bone ratio&lt;/span&gt;&lt;span lang="IN"&gt;,&lt;/span&gt;&lt;span lang="EN-US"&gt; and meat chemical composition of Sensi-1 Agrinak chicken, reared until 10 weeks of age. Two hundred and sixteen of unsexed day old chickens (DOC) of Sensi-1 Agrinak were subjected to six experimental rations differed in dietary crude protein (CP) content,. &lt;/span&gt;&lt;span lang="IN"&gt;Namely:&lt;/span&gt;&lt;span lang="EN-US"&gt; 21;19; and 17 % and dietary metabolizable energy (ME) (2800 and 3000 kcal/kg). Each treatment combination was replicated four times and fed from day old to 10 weeks old. In each treatment combination there were nine unsexed-DOCs. The parameters observed were performance (i.e. live weight, feed intake, viability, FCR), economic index (European Production Efficiency Factor/EPEF), meat bone ratio, and meat chemical composition. &lt;/span&gt;&lt;span lang="IN"&gt;R&lt;/span&gt;&lt;span lang="EN-US"&gt;esult showed that &lt;/span&gt;&lt;span lang="EN-US"&gt;increas&lt;/span&gt;&lt;span lang="IN"&gt;ed&lt;/span&gt;&lt;span lang="EN-US"&gt; of dietary CP level increased live weight and EPEF (p&amp;lt;0.05). Sensi-1 Agrinak chicken had the best FCR (2.59), when fed diet containing 21% CP and 3000 kcal/kg. Increas&lt;/span&gt;&lt;span lang="IN"&gt;ed&lt;/span&gt;&lt;span lang="EN-US"&gt; dietary CP level increased the meat-bone ratio of breast, thighs, and drumsticks. Meanwhile, increas&lt;/span&gt;&lt;span lang="IN"&gt;ed&lt;/span&gt;&lt;span lang="EN-US"&gt; levels of dietary CP and ME did not affect (p&amp;gt;0.05) meat chemical composition. It &lt;/span&gt;&lt;span lang="IN"&gt;is&lt;/span&gt;&lt;span lang="EN-US"&gt; concluded that optimal dietary levels of crude protein and energy for unsexed Sensi-1 Agrinak chicken up to 10 weeks of age were 21% CP and 3000 kcal/kg.&lt;/span&gt;&lt;/p&gt;

Effects of dietary vitamin B1 on growth performance, intestinal digestion and absorption, intestinal microflora and immune response of juvenile golden pompano (Trachinotus ovatus)

The study was conducted to investigate the effects of dietary vitamin B1 on growth performance, intestinal digestion and absorption, intestinal microflora, and the immune response of juvenile golden pompano. Six isonitrogenous and isolipidic diets were formulated, containing diet-1 (0 mg/kg), diet-2 (4.88 mg/kg), diet-3 (8.15 mg/kg), diet-4 (12.00 mg/kg), diet-5 (17.40 mg/kg) and diet-6 (20.40 mg/kg) of vitamin B1. The diets were fed to juvenile golden pompano (initial body weight:11.20 ± 0.15 g) for 8 weeks. The study indicated that dietary vitamin B1 significantly increased weight gain rate (WGR) (P < .05), specific growth rate (SGR) (P < .05), and feed efficiency ratio (FER) (P < .05) of golden pompano. Dietary vitamin B1 levels had a significant effect on serum total cholesterol (TC) (P < .05), glucose (GLU) (P < .05), C4 complement (C4) (P < .05) and lysozyme (LZM) (P < .05). A diet supplemented with 12.00 mg/kg vitamin B1 increased the activities of hepatic total antioxidant capacity catalase (CAT) (P < .05), superoxide dismutase (SOD) (P < .05), glutathione peroxidase (GPX) (P < .05), glutathione reductase (GR) (P < .05), transketolase (TK) (P < .05) and hepatic vitamin B1 accumulation (P < .05), decreasing the activities of hepatic malondialdehyde (MDA) (P < .05). A diet supplemented with 12.00 mg/kg vitamin B1 improved intestinal digestion and absorption by increasing the activities of intestinal chymotrypsin (P < .05), γ-glutamyl transferase (γ-GT) (P < .05), and creatine kinase (CK) (P < .05). Dietary vitamin B1 also increased the intestinal microvilli length and microvilli numbers to a certain degree. Dietary vitamin B1 increased the richness and the diversity of the microbial community (P < .05; Tukey test). Dietary vitamin B1 increased the number of Pseudomonas and restricted the number of Mycoplasma and E. shigella in intestine. A quadratic regression analysis on weight gain and hepatic vitamin B1 concentrations indicated that the optimum dietary vitamin B1 levels for the optimal growth of juvenile pompano were 12.94 and 12.61 mg/kg, respectively.

Dietary chromium polynicotinate improves growth performance and feed utilization of juvenile golden pompano (Trachinotus ovatus) with starch as the carbohydrate

This study was conducted to determine if the level of dietary chromium polynicotinate (Cr-Nic) affects growth and feed utilization of juvenile golden pompano (Trachinotus ovatus). Fish were fed one of six diets each containing 42% crude protein (CP) and supplemented with 0 (42% CP-basal-0), 5, 10, 20, 40 or 80 mg of Cr-Nic kg−1. A diet containing 48% CP and without Cr-Nic supplementation (48% CP-basal-0) was also formulated. Wheat starch was used as the carbohydrate source for each diet. The treatment diets were fed to triplicate groups of pompano fish with initial body weights of 10.8 ± 0.18 g for 8 weeks. Fish fed diets supplemented with 10 mg kg−1 Cr-Nic had the highest weight gain percentage (WG%), which was significantly higher than that of fish fed the 42% CP-basal-0 diet. The feed efficiency (FE) of fish fed the 48% CP-basal-0 diet was higher than that of fish fed the 42% CP-basal-0 diet. However, there was no significant difference in FE among fish fed the 48% CP-basal-0 diet and 42% CP-diets that had been supplemented with Cr-Nic. Protein efficiency ratio (PER) was highest for fish fed diets supplemented with 10 and 20 mg kg−1 Cr-Nic, followed by those containing 5, 40, 80 mg kg−1 Cr-Nic and the 48% CP-basal-0 diet. It was lowest for fish fed the 42% CP-basal-0 diet. Analysis of WG by second-order regression indicated that the optimal dietary level of Cr-Nic for T. ovatus is 16.0 mg kg−1. Thus, based on the results of this study, the minimum Cr-Nic requirement was established for golden pompano at 16 mg kg−1 and suggested to be supplemented in diets for this species.

Immunostimulating effects of Ginkgo biloba extract against toxicity induced by organophosphate pesticide, diazinon in rainbow trout, Oncorhynchus mykiss: innate immunity components and immune-related genes.

The immunostimulating and therapeutic properties of Ginkgo biloba (GB) have always been the focus of traditional medicine over thousands of years. During last decade, special attentions were paid to use of GB in aquaculture to enhance fish health and survival. In the present study, we investigated for the first time the immunogenic effects of dietary GB against oxidative and toxicity induced by organophosphate pesticide, diazinon. In non-diazinon-exposed fish, the plasma total immunoglobulin, lysozyme activity, and peroxidase activity significantly elevated after 60-day experiment in fish supplemented with 1 and 2g GB/kg diet (p < 0.05). The respiratory burst activity and complement activity significantly increased only in groups supplemented with 0.5g GB/kg diet (p < 0.05). Furthermore, the peroxidase activity, total immunoglobulin, and lysozyme activity significantly declined in groups supplemented with 4g GB/kg diet during feeding trial (p < 0.05). There were no significant differences in expression of interleukin 1 beta (IL-1β) and transforming growth factor beta 1 (TGF-β1) genes in kidney between control group (non-GB-supplemented fish) and GB-supplemented fish (p > 0.05). In diazinon-exposed fish, all immunity components significantly decreased during exposure in control and those fed 0.5 and 4g GB/kg diet (p < 0.05). In fish fed 1 and 2g GB/kg diet, no alternations were found in immunity components during exposure period (p > 0.05). In addition, diazinon induced the expression of IL-1β and TGF-β1 genes in control and fish fed 0.5 and 4g GB/kg diet (p < 0.05). No significant changes were observed in expression of IL-1β and TGF-β1 genes in fish supplemented with 1 and 2g GB/kg (p > 0.05). In conclusion, the results of the present study suggest an immunogenic role for dietary GB at optimum dietary levels (1-2g GB/kg diet) against toxicity induced by diazinon. Nevertheless, GB at high dietary levels (4g GB/kg diet) showed immunosuppressive effects, which makes it necessary to optimize its levels in diet.

Dietary oregano extract (Origanum vulgare L.) enhances the antioxidant defence in rainbow trout, Oncorhynchus mykiss against toxicity induced by organophosphorus pesticide, diazinon

Moderating effects of oregano extract (Origanum vulgare L.) on oxidative stress and toxicity induced by organophosphate pesticide, diazinon (0.287 mg/l) were investigated for the first time in rainbow trout, Oncorhynchus mykiss by measuring antioxidant and metabolic enzymes. In non-diazinon-exposed fish, the hepatic levels of total antioxidant capacity (TAC) and antioxidant enzymes including superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPX) elevated in fish supplemented with 6 and 10 g ORG/kg diet compared to control group (non-ORG-supplemented fish). The supplementation of fish with 14 g ORG/kg diet significantly decreased the hepatic antioxidant enzymes compared to control. The acetylcholinesterase (AChE) activity and malondialdehyde (MDA) levels remained unchanged in all groups throughout the experiment. The serum levels of hepatic metabolic enzymes [(aspartate aminotransferase (AST), alanine aminotransferase (ALT), and lactate dehydrogenase (LHD)] remained unchanged in all experimental groups throughout the experiment. In diazinon-exposed groups, the activity of SOD, GPx, and TAC in liver elevated after exposure to diazinon in fish fed 2, 6, and 10 g ORG/kg diet. The CAT activity increased only in fish supplemented with 6 and 10 g ORG/kg diet. The levels of all antioxidant enzymes and TAC significantly decreased in control and fish supplemented with 14 g ORG/kg diet. The AChE activity significantly declined in control and fish supplemented with 2 and 14 g ORG/kg diet. After exposure to diazinon, the levels of MDA in liver increased in control and those fed 2 and 14 g ORG/kg diet. In fish supplemented with 6 and 10 g ORG/kg diet, the MDA levels showed no significant alternations during the experiment period. The serum levels of AST, ALT, and alkaline phosphatase (ALP) elevated during exposure to diazinon in control and fish supplemented with 2 and 14 g ORG/kg diet, while these enzymes showed no significant changes in fish fed with 6 and 10 g ORG/kg diet. In conclusion, our results showed that ORG at optimum dietary levels (6 and 10 g ORG/kg diet) could moderate the toxicity induced by diazinon in rainbow trout by enhancing the liver antioxidant system and protecting the hepatocytes. Furthermore, the high dietary levels of ORG caused toxic effects on antioxidant enzymes and hepatocytes, which this makes it necessary to optimize its levels in the diet.

Effects of organic zinc on tibia quality, mineral deposit, and metallothionein expression level of aged hens

ABSTRACTThe study aimed to determine the effects of methionine hydroxy analog chelate zinc on the tibia quality, mineral deposit, apparent retention of nutrients, and liver metallothionein (MT) expression level of aged laying hens. A total of 960 layers (Hy-Line Grey, 57 wk old) were randomly assigned into 4 groups, and each group had 8 replicates of 30 hens. During the first 2 wk, groups were fed a basal diet without extra zinc (Zn: 35.08 mg/kg). During the ensuing 14 wk, 4 levels of Zn (inorganic Zn: 80 mg/kg; organic Zn: 20, 40, 80 mg/kg) were added to the diet. The results indicated that both the Zn source and level did influence tibia strength and calcium (Ca) and Zn concentrations of tibia (P < 0.05), whereas there were no differences in the copper (Cu) and phosphorus (P) concentrations of the tibia and the tibia length (P > 0.05). Moreover, dietary supplementation with 40 or 80 mg/kg of organic Zn showed higher Zn and Ca concentrations in the tibia and higher tibia strength. The Cu concentration in the liver showed no difference among the 4 treatments, whereas the Zn concentration in the liver increased with the increasing Zn level. The apparent retention of P, iron (Fe), and manganese (Mn) was not affected by the Zn level or source (P > 0.05). However, the organic Zn group increased the apparent retention of Cu, Zn, Ca, crude protein (CP), and energy, and the group supplemented with 40 or 80 mg/kg of organic Zn obtained significant effects (P < 0.05). Moreover, dietary supplementation with 40 or 80 mg/kg organic Zn increased the MT mRNA expression of the liver at week 72, whereas 20 mg/kg of organic Zn decreased it (P < 0.05). In conclusion, this study suggested that an optimum dietary (40 mg/kg) organic Zn level plays a key role in promoting the apparent retention of minerals and nutrients, trace element deposit, and MT mRNA expression.

Effects of Dietary Niacin on Growth Performance, Serum Biochemistry, Antioxidant Ability of Liver, Intestinal Digestion, and Absorption in Juvenile Golden Pompano

Six groups of experimental diets containing different levels (14.9, 22.4, 28.6, 37.9, 42.0 and 77.5 mg/kg) of niacin were formulated. Juvenile golden pompano (initial body weight:7.82±0.07 g) were fed in cages for eight weeks. Results showed that moderate niacin in the diet significantly increased (P&lt;0.05) weight gain rate (WGR), specific growth rate (SGR), and feed efficiency (FER). Dietary niacin levels increased the protein content in whole fish and muscle (P &lt; 0.05). The content of serum high density lipoprotein cholesterol (HDL-C) and total cholesterol (TCHO) increased significantly and triglyceride (TG) content decreased significantly (P&lt;0.05). C3 and C4 content in serum, and activities of lysozyme (LZM), and alkaline phosphatase (ALP) increased significantly (P&lt;0.05). Dietary niacin levels significantly increased (P&lt;0. 05) the catalase (CAT), alkaline phosphatase (ALP), and total antioxidant capacity (T-AOC) of the liver when niacin content was more than 28.6 mg/kg. Dietary niacin levels also improved intestinal digestion and absorption by increasing glutamyl transferase (γ-GT)activity. Quadratic regression analysis on WGR indicated that the optimum dietary niacin level for optimal growth of juvenile golden pompano was 29.85 mg/kg.

PSXIII-18 The optimum dietary forage inclusion level for finishing cattle fed diets containing corn dried distillers grains.

PSXIII-18 The optimum dietary forage inclusion level for finishing cattle fed diets containing corn dried distillers grains.

Evaluation of a single-cell protein as a dietary fish meal substitute for whiteleg shrimp Litopenaeus vannamei

A 9-week feeding trial was conducted to evaluate the optimum dietary level of PROTIDE (PRO), a single-cell protein obtained from the bacteria Corynebacterium ammoniagenes, as a substitute for fish meal in the diet of whiteleg shrimp Litopenaeus vannamei. Five diets were formulated that replaced fish meal at 0% (PRO0), 10% (PRO2), 20% (PRO4), 30% (PRO6) and 40% (PRO8). Fifty shrimp averaging 0.15 ± 0.02 g (mean ± SD) body weight were randomly distributed between 20 experimental tanks and fed one of the five experimental diets. At the end of the experiment, final weight, weight gain, specific growth rate and feed conversion ratio of shrimp fed PRO0 and PRO2 diets were significantly improved compared to those fed PRO6 and PRO8 diets (P < 0.05). The proximate composition of muscle and the whole body indicated an increase in crude protein content with an increase in dietary PRO level. These results suggest that, for whiteleg shrimp, the optimum dietary level of PRO when used as a replacement for fish meal should be greater than 10% (PRO2) but less than 20% (PRO4) without any additional dietary amino acid supplementation.

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

We evaluated the dietary fish meal analogue as a fish meal replacer based on growth, hematology, non-specific immune responses and intestinal integrity in growing Japanese eel, Anguilla japonica. Five experimental diets contained the animal protein sources as 100% FM (FMA0) as control, 90% FM + 10% FMA (FMA10), 80% FM + 20% FMA (FMA20), 70% FM + 30% FMA (FMA30) and 60% FM + 40% FMA (FMA40). Each group of 13 fish with an average initial body weight of 119.60 ± 0.97 g (mean ± SD) were randomly distributed into 15 tanks (250-L each) in triplicates and fish were fed twice a day with one of the 5 experimental diets for 10 weeks. At the end of the feeding trial, weight gain (WG), specific growth rate (SGR), feed intake (FI) and feed efficiency (FE) of fish fed the FMA0, FMA10, and FMA20 diets were significantly higher than those of fish fed the FMA30 and FMA40 diets. Whole body proximate composition and amino acids profile of fish were not affected by dietary treatments. Broken-line regression analysis indicates the optimum dietary FMA replacement level could be 15.39%. Hemato-biochemical parameters such as aspartate aminotransferase (AST), alanine aminotransferase (ALT), and triglycerides (TG) were higher in fish fed the FMA30 and FMA40 diets than those of fish fed the FMA0, FMA10, and FMA20 diets. Non-specific immune responses in terms of serum superoxide dismutase (SOD) and lysozyme activities were unaffected among fish fed the diets. Distal intestinal histology of fish fed the FMA30 and FMA40 diets showed abnormal villi structural arrangements (fold breaks, dilation, and dwarf villi) compared to those of fish fed the FMA0, FMA10, and FMA20 diets. Therefore, the results indicated that the optimum level of dietary FMA could fall between 15.39% and 20% in growing Japanese eel.

Effects of dietary replacement of fish oil by vegetable oil on proximate composition and odor profile of hepatopancreas and gonad of Chinese mitten crab (Eriocheir sinensis).

Five different diets with different ratio of fish oil to vegetable oil were prepared. The biological index and proximate composition of Eriocheir sinensis fed with different diets were compared, and then sensory analysis, electronic nose (E-nose) and headspace-solid phase micro-extraction combined with gas chromatography-mass spectrometer (HS-SPME-GC-MS) analysis were applied to determine the odor profile of E. sinensis. The results showed that partial replacement (50%-75%) of fish oil by vegetable oil (FO/VO) was beneficial to the weight increment, nutrition accumulation, and odor-active compounds (OACs) formation of E. sinensis. A total of 7 and 11 OACs were detected in the hepatopancreas and gonad, respectively, these OACs contributed greatly to the overall odor profiles of E. sinensis when the dietary replacement levels were at 50% and 75%, respectively. The results could provide the guide for dietary fish oil replacement as well as improving the odor quality of E. sinensis. Practical application The objective of this research is to compare the effects of dietary replacement of fish oil by vegetable oil on proximate composition and odor profiles of E.sinensis. The results obtained from this study would not only chose an optimal dietary replacement level and serve as a useful database for the odor of female and crabs, but also provide some guide for the improvement of Chinese mitten crab aquaculture.

Dietary protein requirement of Pacific white shrimp Litopenaeus vannamei in three different growth stages

A study of three feeding trials was conducted to investigate the dietary protein requirements of Pacific white shrimp (Litopenaeus vannamei) at three different growth stages. Six experimental diets were formulated to include increasing protein levels of 25, 30, 35, 40, 45, and 50% (designated as P25, P30, P35, P40, P45, and P50, respectively) for three feeding trials. The three feeding trials were conducted in different-sized shrimp at 0.65 g (trial 1), 4.80 g (trial 2), and 10.5 g (trial 3). Triplicate groups of shrimp were fed one of the experimental diets for 36, 42, and 48 days in trials 1, 2, and 3, respectively. In trial 1, the growth performance was not affected by the dietary protein levels. However, protein efficiency ratio was significantly higher in P30 diet compared to P40, P45, and P50 diets. In trial 2, growth rate was significantly higher in P35 diet than in P25 diet. In trial 3, the lowest growth performance was obtained in P25 diet which significantly differed from that of other experimental diets. Broken line analysis of growth data indicates that the optimal dietary level of crude protein is 34.5, 35.6, and 32.2% for small-, medium-, and large-sized (juvenile, sub-adult, and adult stages) Pacific white shrimp, respectively.

Impact of Dietary Cornstarch Levels on Growth Performance, Body Composition and Digestive Enzyme Activities of Juvenile Soft-Shelled Turtle (Pelodiscus sinensis)

Abstract We conducted an 8-week feeding trial to determine the effects of dietary starch levels on growth performance, body composition, and digestive enzyme activities of juvenile soft-shelled turtles. Six fish meal-based diets containing 120, 180, 240, 300, 360 and 420 g kg−1 cornstarch were formulated. Body weight gain (BWG), crude protein concentration in whole body, as well as protease activity increased with increasing dietary starch levels until the highest at 240–300 g kg−1, but it was decreased at higher dietary starch content. In contrast, the feed conversion ratio, moisture content and hepatosomatic index were the lowest at 240–300 g kg−1 of cornstarch. The weight gain correlated significantly with the survival rate, the crude protein composition and the protease activity, but correlated negatively to the moisture content and the hepatosomatic index. The optimal dietary starch levels for the maximum BWG and maximum protease activity were 267.25 g kg−1 and 266.79 g kg−1, respectively. The α-amylase activity was the lowest at 120 g · kg−1 of cornstarch, and increased with increasing cornstrach content. The lipase activity and the amount of crude lipid in the turtles were not influenced by dietary cornstarch. Our results suggest that around 300 g kg−1 of cornstarch in diets is optimal for juvenile soft-shelled turtles.

Dietary magnesium deficiency impaired intestinal structural integrity in grass carp (Ctenopharyngodon idella)

Grass carp (223.85–757.33 g) were fed diets supplemented with magnesium (73.54–1054.53 mg/kg) for 60 days to explore the impacts of magnesium deficiency on the growth and intestinal structural integrity of the fish. The results demonstrated that magnesium deficiency suppressed the growth and damaged the intestinal structural integrity of the fish. We first demonstrated that magnesium is partly involved in (1) attenuating antioxidant ability by suppressing Nrf2 signalling to decrease antioxidant enzyme mRNA levels and activities (except CuZnSOD mRNA levels and activities); (2) aggravating apoptosis by activating JNK (not p38MAPK) signalling to upregulate proapoptotic protein (Apaf-1, Bax and FasL) and caspase-2, -3, -7, -8 and -9 gene expression but downregulate antiapoptotic protein (Bcl-2, IAP and Mcl-1b) gene expression; (3) weakening the function of tight junctional complexes (TJs) by promoting myosin light chain kinase (MLCK) signalling to downregulate TJ gene expression [except claudin-7, ZO-2b and claudin-15 gene expression]. Additionally, based on percent weight gain (PWG), against reactive oxygen species (ROS), against caspase-9 and claudin-3c in grass carp, the optimal dietary magnesium levels were calculated to be 770.38, 839.86, 856.79 and 811.49 mg/kg, respectively.

Effects of dietary arginine on intestinal antioxidant status and immunity involved in Nrf2 and NF-κB signaling pathway in juvenile blunt snout bream, Megalobrama amblycephala

The present study assessed the effects of dietary arginine on intestinal antioxidant status and immunity involved in Nrf2 and NF-κB signaling pathway in juvenile blunt snout bream. Fish were fed three practical diets with graded arginine levels (0.87%, 1.62% and 2.70%) for 8 weeks. Compared with the control group (0.87%), the counts of white blood cell (WBC), red blood cell (RBC) and hemoglobin (HGB) content were significantly improved at dietary arginine levels of 1.62% (P<0.05). Plasma albumin (ALB) levels and alkaline phosphatase (ALP) activities were significantly improved at dietary arginine levels of 1.62% and 2.70% (P < 0.05). Alanine transaminase (ALT) activity was decreased in fish fed with 1.62% dietary arginine level (P<0.05). Plasma glutathione peroxidase (GPx) activities, copper-zinc superoxide dismutase (Cu/Zn-SOD) activities, total antioxidant capacity (T-AOC) activities and glutathione (GSH) levels were significantly increased at dietary arginine levels of 1.62% and 2.70% (P<0.05). Plasma total superoxide dismutase (T-SOD) activities and catalase (CAT) activities were significantly improved in fish fed with 1.62% dietary arginine level. Significantly higher manganese superoxide dismutase (Mn-SOD) activity was observed in fish fed with 1.62% dietary arginine level compared with 2.70% dietary arginine level (P<0.05). 1.62% and 2.70% dietary arginine levels significantly lowered malondialdehyde (MDA) levels. The relative expression of nuclear factor erythroid 2-related factor 2 (Nrf2) was significantly increased in fish fed with 1.62% dietary arginine level, inversely, the relative expression of Kelch-like ECH-associated protein 1 (Keap1) showed a converse trend. 1.62% and 2.70% dietary arginine levels significantly improved the relative expressions of Cu/Zn-SOD, GPx and CAT. Furthermore, 2.70% dietary arginine level significantly lowered the relative expression of Mn-SOD compared with the control group and 1.62% dietary arginine levels. The relative expressions of Interleukin 1β (IL-1β), tumour necrosis factor-α (TNF-α) and nuclear factor-kappa B (NF-κB) were lowered in fish fed with 1.62% dietary arginine level. 1.62% and 2.70% dietary arginine levels significantly improved the relative expressions of transforming growth factor-β (TGF-β). Hematocrit (HCT), aspartate aminotransferase (AST) activities, interleukin 8 (IL-8) and interleukin 10 (IL-10) expressions were not significantly affected by the graded dietary arginine levels. These results suggest that the optimal dietary arginine level plays an important role in enhancing antioxidant and immune status to maintain the intestinal health of juvenile blunt snout bream.

GROWTH PERFORMANCE AND ENZYME ACTIVITIES IN CATFISH [Pangasianodon hypophthalmus] FED WITH WATER HYACINTH-BASED DIET

An alternative subtitution of pollard as an imported feed ingredient is a neccesity and one of the potential ingredients is water hyacinth (Eichhornia crassipes). This study was conducted to evaluate growth performance and enzyme activity in catfish (Pangasianodon hypophthalmus). Diet with five different levels of water hyacinth subtitute of pollard (0%, 25%, 50%, 75%, and 100%) were fed to catfish for 60 days. Seventy (70) catfish fry with average initial body weight of 2.45±0.15 g were maintained in 100cm x 80cm x 60cm aquaria. Fish fed at satiation level three times daily at 8 am, 12 pm, and 4 pm. With dietary of 25% water hyacinth, growth performance and protease activity similar to 0% treatment. Feed intake, protein digestibility, feed efficiency, protein efficiency ratio, and protease and amylase enzyme activities decreased (p&lt;0.05) in those fed with more than 25% water hyacinth. Catfish fed 25% water hyacinth showed significantly (p&lt;0.05) higher daily growth rate, feed efficiency and protein digestibility than those with other treatments. Based on the growth performance and enzyme activity, we can conclude that the optimum dietary level of water hyacinth subtitute pollard for fry catfish is 25%.

The importance of phospholipids combined with long-chain PUFA in formulated diets for pikeperch (Sander lucioperca) larvae.

Dietary phosphoglycerides and n-3 long-chain PUFA (LC-PUFA) play important functions in the development of pikeperch (Sander lucioperca) larvae. This study aimed to determine optimal dietary levels of soyabean lecithin (SBL)-derived phospholipids (PL) in starter feeds for pikeperch larvae 10-30 d post-hatch (DPH) and examine performance and ontogeny by additional supplementation of n-3 LC-PUFA in the form of Algatrium DHA 70 (glyceride product; 660-700 mg/g DHA; EPA 60-75 mg/g). In total, six isoproteic and isoenergetic extruded diets were formulated with increasing levels of PL (3·7, 8·3 or 14·5 % wet weight (w.w.), respectively); however, three of the diets were supplemented with three levels of Algatrium DHA 70 (0·6, 2·0 or 3·4 %, respectively). Liver proteomic analyses of larvae at 30 DPH were included for effects of PL and primarily DHA on performance, physiological expression and interactions in larval proteins. In addition, bone anomalies, digestive enzymatic activity, candidate gene expression and skeleton morphogenesis were examined. Results confirmed the importance of dietary PL levels of at least 8·2 % w.w., and an additional beneficiary effect of supplementation with DHA plus EPA. Thus, combined supplementation of SBL (up to 14·51 % w.w. PL) and n-3 LC-PUFA (1·004 % DM DHA and 0·169 % DM EPA) in the form of TAG resulted in highest growth and lowest incidence of anomalies, improved digestive enzyme activity and had differential effect on liver proteomics. The results denote that essential fatty acids can be supplemented as TAG to have beneficial effects in pikeperch larvae development.