Dietary Supplementation of Zinc Nanoparticles and Its Influence on Biology,Physiology and Immune Responses of the Freshwater Prawn,Macrobrachium rosenbergii

The present study was conducted to assess the influence of dietary zinc nanoparticles (size 50 nm) on the growth, biochemical constituents, enzymatic antioxidant levels and the nonspecific immune response of the freshwater prawn, Macrobrachium rosenbergii post larvae (PL). The concentrations of dietary supplement zinc nanoparticles (ZnNPs) were 0, 10, 20, 40, 60 and 80 mg kg^?1 with the basal diet, and the level of Zn in ZnNP-supplemented diets were 0.71, 10.61, 20.73, 40.73, 60.61 and 80.60 mg kg^?1, respectively. ZnNP-incorporated diets were fed to M. rosenbergii PL (initial body weight, 0.18?±?0.02 g) in a triplicate experimental setup for a period of 90 days. ZnNP supplemented feed fed PL up to 60 mg kg^?1 showed significantly (P?<?0.05) improved performance in survival, growth and activities of digestive enzymes (protease, amylase and lipase). The concentrations of biochemical constituents (total protein, total amino acid, total carbohydrate and total lipid), total haemocyte count and differential haemocyte count were elevated in 10–60 mg kg^?1 ZnNP supplemented feed fed PL. However, the PL fed with 80 mg ZnNPs kg^?1 showed negative results. Activities of enzymatic antioxidants [superoxide dismutase (SOD) and catalase (CAT)], metabolic enzymes [glutamate–oxaloacetate transaminase (GOT) and glutamate–pyruvate transaminase (GPT)] and the process of lipid peroxidation (LPO) in the hepatopancreas and muscle showed no significant alterations in 10–60 mg kg^?1 ZnNP supplemented feed fed PL. Whereas, 80 mg ZnNPs kg^?1 supplemented feed fed PL showed significant elevations in SOD, CAT, LPO, GOT and GPT. Therefore, 80 mg ZnNPs kg^?1 was found to be toxic to M. rosenbergii PL. Thus, the study suggests that up to 60 mg ZnNPs kg^?1 can be supplemented for regulating survival, growth and immunity of M. rosenbergii.     

Combined or Individual Effects of Dietary Probiotic <Emphasis Type="Italic">Pedicoccus acidilactici</Emphasis> and Nucleotide on Growth Performance,Intestinal Microbiota,Hemato-biochemical Parameters,and Innate Immune Response in Goldfish (<Emphasis Type="Italic">Carassius auratus</Emphasis>)

This study investigated the effect of dietary supplementation of probiotic Pedicoccus acidilactici and nucleotide (separately or combined) on growth performance, intestinal microbiota, hemato-immunological parameters, and immunity response in goldfish (Carassius auratus). Fish (average weight 5–6 g) were acclimatized and divided into eight experimental diets supplemented with P. acidilactici of different concentrations (0.1, 0.2, and 0.3% diet) and nucleotides (0 and 0.5% diet) for 6 months. Fish fed with experimental diets showed significant differences in terms of final weight, weight gain, feed conversion ratio, daily growth rate, and condition factor when compared to control diet (P < 0.05). Fish fed with probiotic (0.3%) separately and combined with nucleotide (0.5%) had highest RBC and WBC when compared to other diets (P < 0.05), while the highest values for Hb and Hct as well as total protein, glucose, albumin, and globulin were observed in probiotic (0.2%) and nucleotide (0.5%) combined diet. Serum lysozyme and anti-protease activities were significantly higher in probiotic (0.1 and 0.2%) and nucleotide (0.5%) combined diets. Similarly, these two diets combined showed the highest colonization of P. acidilactici when compared to other diets. In conclusion, combined dietary probiotic and nucleotide improve the growth performance, hemato-biochemical parameters, and intestine growth in C. auratus.     

Effects of dietary l‐carnitine supplements on growth and body composition in beluga sturgeon (Huso huso) juveniles

The effects of dietary l ‐carnitine on growth performance, whole body composition and feed utilization were studied in beluga, Huso huso. Fish were randomly allocated in 15 tanks (30 fish per tank) and triplicate groups were fed to satiety during 84 days one of five isonitrogenous (41% CP) and isoenergetic (20 MJ kg^?1) diets, each differing in l ‐carnitine content [0 (control), 300, 600, 900 and 1200 mg kg^?1 diet]. At the end of the trial, fish grew from 19‐ to 23‐fold in weight, from 8.4 g to a maximum of 191 g. Fish fed 300–600 mg l ‐carnitine had the highest specific growth rate (SGR, 3.69 and 3.72% day^?1) and protein efficiency ratio (PER, 0.95 and 0.99), and the lowest feed conversion ratio (FCR, 1.4 and 1.3) than the other groups (P < 0.0001). SGR, PER and FCR were the poorest for fish fed 1200 mg l ‐carnitine, while fish fed the unsupplemented and 900 mg l ‐carnitine supplemented diet showed intermediate performance. Body lipid concentration decreased significantly from 5.8 to 5.1% (P < 0.0001) with dietary l ‐carnitine supplementation increasing from 0 to 300 mg. Energy content was significantly lower in fish fed the 900 and 1200 mg l ‐carnitine diet (5.8 MJ kg^?1), when compared with the other treatment groups (6.4–6.6 MJ kg^?1). The results indicated that feeding sturgeon on diets supplemented with 300 mg l ‐carnitine kg^?1 diet improved growth performance, and stimulated protein‐sparing effects from lipids.     

Dietary vitamin A requirement of juvenile Amur sturgeon (Acipenser schrenckii)

The present experiment was conducted to determine the dietary vitamin A requirement of juvenile Amur sturgeon (Acipenser schrenckii) by formulating seven semipurified diets containing 10, 258, 510, 1050, 2020, 4100 and 8300 IU vitamin A (as retinol acetate) kg^?1 diet, respectively. Each experimental diet was fed to triplicate groups of 20 juveniles each with initial average weights of 12.09 ± 0.22 g in 405‐L aquaria and maintained at 25.0 ± 2.0°C for 8 weeks. Fish fed the basal diet (10 IU vitamin A kg^?1 diet) exhibited poor appetite and activity, whereas these signs were not observed in any group fed vitamin A‐supplemented diets. Weight gain, feed efficiency and hepatosomatic index increased significantly with increases in the dietary vitamin A level, reaching a peak with the vitamin A 1050 IU kg^?1 diet, and then decreasing. Muscle chemical compositions were not affected by the dietary vitamin A levels. Vitamin A concentrations in liver and muscle increased significantly as the vitamin A levels increased within a range of 10～4100 IU kg^?1 diet; above this level there were no significant changes. Broken‐line regression analysis of weight gain and liver vitamin A concentration against the dietary vitamin A level showed that juvenile Amur sturgeon required a minimum of 923 IU vitamin A kg^?1 in the diet for maximal growth, and 1981 IU kg^?1 for highest liver vitamin A accumulation.     

The potential effects of antioxidant feed additives in mitigating the adverse effects of corn naturally contaminated with <Emphasis Type="Italic">Fusarium</Emphasis> mycotoxins on antioxidant systems in the intestinal mucosa,plasma, and liver in weaned pigs

Seventy-two piglets (6.0 kg BW) were randomly distributed within six different dietary treatments to evaluate the effect of deoxynivalenol (DON) and the potential of four antioxidant feed additives in mitigating the adverse effects of DON on growth performances and oxidative status. Dietary treatments were as follows: control diet 0.8 mg/kg DON; contaminated diet (DON-contaminated diet) 3.1 mg/kg DON; and four contaminated diets, each supplemented with a different antioxidant feed additive, DON + vitamins, DON + organic selenium (Se)/glutathione (GSH), DON + quercetin, and DON + COMB (vitamins + Se/GSH + quercetin from the other treatments). Although DON was the main mycotoxin in the contaminated diet, this diet also contained 1.8 mg/kg of zearalenone (ZEN). The “mycotoxin” effects therefore included the combined effect of these two mycotoxins, DON, and ZEN. The DON-ZEN ingestion did not affect growth performances, average daily gain (ADG), average daily feed intake (ADFI), and feed efficiency (G:F ratio), but partially induced oxidative stress in weaned pigs as shown by increased malondialdehyde (MDA) content in the plasma and superoxide dismutase (SOD) activity in liver (P?<?0.05). However, no change in the activity of other antioxidant enzymes or GSH concentrations was observed in plasma and liver of piglets fed the DON-contaminated diet (P?>?0.05). Supplementation with individual antioxidant feed additive had a limited effect in weaned pigs fed DON-ZEN-contaminated diets. Combination of antioxidants (vitamins A, C, and E, quercetin, and organic Se/GSH) reduced plasma and liver MDA content and SOD activity in liver (P?<?0.05) of piglets fed DON-ZEN-contaminated diets. Furthermore, this combination also reduced MDA content in the ileum (P?<?0.05), although activity of glutathione peroxidases (GPx), SOD or catalase (CAT) in the ileum was not affected by DON-ZEN contamination or antioxidant supplements. In conclusion, DON-ZEN contamination induced oxidative stress in weaned pigs and combination of antioxidant feed additives restored partially the oxidative status. Further studies will be necessary to assess whether the effects of antioxidant feed additives on oxidative status are specific when feed is contaminated with DON-ZEN.     

Effects of dietary thymol‐carvacrol on growth performance,hematological parameters and tissue composition of juvenile rainbow trout,Oncorhynchus mykiss

Growth performance, carcass quality, survival and hematological responses of Oncorhynchus mykiss juveniles (initial weight 8.4 ± 0.1 g) fed diets containing thymol‐carvacrol powder at the levels of 0, 1.0, 2.0, 3.0 g kg^?1 were tested. Thymol‐carvacrol powder originated from Origanum vulgare, a Mediterranean plant, added to diets. Each diet was fed to triplicate groups of fish for 45 days. Fish fed diets containing thymol‐carvacrol had significantly higher final weight and growth than the control group. Food conversion ratio in fish fed diets containing 2.0 and 3.0 g kg^?1 thymol‐carvacrol was statistically better than in other treatments. Survival was not different among all treatments. The number of lymphocytes increased when thymol‐carvacrol was used at higher levels. Furthermore, whole body lipid content was higher in fish fed 1.0 and 2.0 g kg^?1 thymol‐carvacrol than the other groups, but body protein in the group fed 3.0 g kg^?1 was higher than in other groups. Also, body ash in control and 1.0 g kg^?1 was higher than in other groups. Whole body dry matter was not affected by dietary treatments. These results indicated that dietary administration of thymol‐carvacrol can influence some growth, hematological parameters and tissue composition in rainbow trout juveniles.     

Effects of varying levels of dietary vitamin E (α‐tocopherol) on growth performance,proximate and fatty acid composition of juvenile silver pomfret (Pampus argenteus Euphrasen, 1788)

This study investigated the effects of elevated dietary levels of vitamin E (α‐tocopherol) on growth performance, proximate composition and fatty acid profiles of juvenile silver pomfret, Pampus argenteus. Three semi‐purified experimental diets were formulated to contain 49% protein and 16% lipid. High docosahexaenoic acid (DHA) tuna oil was added to the diets to supplement DHA. A graded level of vitamin E (0‐, 50‐, and 100 mg kg^?1) was added to experimental diets 1 to 3, respectively. Analyzed vit. E levels were 155.2, 195.3 and 236.4 mg kg^?1 in diets 1, 2 and 3, respectively. The experiment was conducted for 12 weeks with juvenile silver pomfret (29.6 ± 7.6 g) using a flow‐through system consisting of nine 1‐m³ tanks. Each treatment had three replicates and fish were stocked at the rate of 20 m^?3. Growth performance and feed utilization parameters of fish fed diets 2 and 3 were significantly (P < 0.05) higher than in fish fed diet 1, but the parameters in diets 2 and 3 did not differ significantly (P > 0.05). Although whole body protein levels were not influenced by the dietary vit. E levels, whole body lipid in fish fed diet 2 was significantly higher than in fish fed the other diets. The whole body vit. E levels in fish fed diet 2 (22.6 mg kg^?1) and diet 3 (24.1 mg kg^?1) were significantly (P < 0.05) higher than in those fed diet 1 (18.2 mg kg^?1). Whole body total saturated fatty acids were significantly lower, and DHA levels higher in fish fed diets 2 and 3 than those fed diet 1. The results of the present study suggest that increasing dietary supplementation of vit. E in high lipid diets enhances the growth performance of fish and that a dietary level of 196 mg kg^?1 vit. E is suitable for the growth of silver pomfret.     

Growth,parasitic infection and hematology in Colossoma macropomum Cuvier, 1818 fed diets containing Allium sativum

The aim of this study was to investigate the effects of a dietary Allium sativum (garlic) addition on growth, parasite infestation and blood parameters in Colossoma macropomum (tambaqui) using 12 net‐cages (1 m³). There were four treatments with three replicates each (15 fish per replicate). Tambaqui of 112.4 g mean weight were fed for 45 days with diets containing 0, 15, 30 and 45 g of fresh garlic kg^?1 feed. Garlic did not affect the tambaqui survival, growth, feed conversion, body condition, plasma glucose levels, total plasma protein levels or red blood cells. Total leukocyte and lymphocyte numbers decreased in fish fed diets containing 45 g garlic kg^?1 feed, but neutrophils decreased in fish fed diets containing 15, 30 and 45 g garlic kg^?1 diet, while the number of immature leukocytes increased in fish fed 30 g and 45 g garlic kg^?1diet. Gills in fish fed 30 and 45 g kg^?1 diet had lower infestation (52% and 63%, respectively) of Anacanthorus spathulatus (Monogenea) compared to controls. The application of garlic in diets improved the response of leukocytes and enhanced the resistance to infections by monogeneans.     

Hemato-Immunological Responses and Disease Resistance in Siberian Sturgeon <Emphasis Type="Italic">Acipenser baerii</Emphasis> Fed on a Supplemented Diet of <Emphasis Type="Italic">Lactobacillus plantarum</Emphasis>

A feeding trial was conducted to investigate the effects of different levels of dietary Lactobacillus plantarum on hemato-immunological parameters and resistance against Streptococcus iniae infection in juvenile Siberian sturgeon Acipenser baerii. Fish (14.6 ± 2.3 g) were fed three experimental diets prepared by supplementing a basal diet with L. plantarum at different concentrations [1 × 10⁷, 1 × 10⁸ and 1 × 10⁹ colony-forming units (cfu) g^?1] and a control (non-supplemented basal) diet for 8 weeks. Innate immune responses (immunoglobulin (Ig), alternative complement activity (ACH50) and lysozyme activity) were significantly higher in fish fed the 1 × 10⁸ and 1 × 10⁹ cfu g^?1 L. plantarum diet compared to the other groups (P < 0.05). Furthermore, fish fed on various levels of L. plantarum significantly showed higher red blood cell (RBC), hemoglobin (Hb), white blood cell (WBC) and monocyte compared to those of the control group (P < 0.05). At the end of the feeding experiment, some fish were challenged with S. iniae to quantify the level of disease resistance. The mortality after S. iniae challenge was decreased in fish fed a probiotic. These results indicated that dietary supplementation of L. plantarum improved immune response and disease resistance of Siberian sturgeon juvenile.     

Immunomodulatory effect of sodium alginate enriched diet in kelp grouper Epinephelus brneus against Streptococcus iniae

The effect of diets containing sodium alginate at 0, 0.5, 1.0, and 2.0 g kg^?1 following challenge with Streptococcus iniae in kelp grouper Epinephelus bruneus were assessed with reference to survival rate and innate immune parameters such as alternative complement, lysozyme, natural haemagglutination, respiratory burst, superoxide dismutase, and phagocytic activities on week 1, 2, and 4. Fish fed with sodium alginate containing diet at 1.0 and 2.0 g kg^?1 after being challenged with S. iniae had higher survival rates of 75% and 60%, respectively than those fed with control diet (0 g kg^?1). With any enriched diet the percentage of macrophages significantly decreased from week 1–4, while the percentage of neutrophils and lymphocytes significantly increased. The alternate complement activity, natural haemagglutination, and phagocytic activities of infected fish fed with sodium alginate containing diet at 1.0 g kg^?1 on week 2 and 1.0 and 2.0 g kg^?1 diets on week 4 were significantly higher when compared to the control. The lysozyme, respiratory bursts, and superoxide dismutase activities of fish fed with enriched diets at 1.0 and 2.0 g kg^?1 were significantly increased on week 2 and 4. We therefore recommend that at 1.0 or 2.0 g kg^?1 dietary administration of sodium alginate can enhance innate immunity and disease resistance in kelp grouper against S. iniae.     

Performance and tissue fatty acid profiles in veal calves fed diets supplemented with conjugated linoleic acids

Three groups of six calves each were fed a milk replacer at 0.8 kg and a starter concentrate ad libitum. Calves of the control group received the basal diet supplemented with rapeseed oil at 10 g per kg of feed solids. Calves of treatment groups were fed diets supplemented with a synthetically produced oil containing 62.3% methyl esters of CLA. The CLA-oil was added to milk at expense of rapeseed oil and fed at 5 and 10 g · kg^?1 feed solids for 63 days. Calves were slaughtered at 115 days of age. There was no significant effect of CLA on growth, intake of starter, feed conversion, chemical composition of meat and its oxidative stability. Dietary supplementation with CLA at 10 g · kg^?1 significantly increased CLA content in m. longissimus dorsi (MLD) from 5.6 to 19.3 mg · 100 g^?1, in liver from 13.1 to 68.8 mg · 100 g^?1, and in perirenal fat from 0.37 to 3.17 g · 100 g^?1. Dietary CLA decreased the ratio of cis-9, trans-11 and trans-10, cis-12 isomers of CLA in tissues, concentration of monounsaturated fatty acids in the MLD and fat, as well as the concentration of fatty acids with 20 and 22 carbon atoms. It can be concluded that in veal calves unprotected CLA apparently escaped ruminal hydrogenation, but was preferentially incorporated into depot fat.     

Partial replacement of monocalcium phosphate with neutral phytase in diets for grass carp,Ctenopharyngodon idellus

A 9‐week experiment was designed to study the effects of partial replacement of monocalcium phosphate (MCP) with neutral phytase on growth, body compositions, serum biochemical statuses and intestinal digestive enzyme activities of grass carp, Ctenopharyngodon idellus. The control diet (designated as P2.0) was prepared with 2.0% MCP but without phytase. The three other diets (designated as PP1.5, PP1.0 and PP0.5, respectively) were supplemented with 1.5, 1.0 and 0.5% MCP, respectively, along with 500 FTU of neutral phytase kg^?1 diet in each. After a 9‐week feeding trial, fish (initial body weight: 43.44 ± 2.37 g) fed with PP1.5 and PP1.0 had no significant change in weight gain (WG), specific growth rate (SGR), protein efficiency rate (PER) or feed conversion ratio (FCR) compared with the control (P > 0.05) whereas fish fed with PP0.5 showed significantly lower growth performance in the above parameters. The crude lipid content in whole body or muscle of the fish fed with PP1.5 was significantly lower than the control while significantly higher in fish fed with PP0.5 (P < 0.05), whereas no obvious change was observed in the fish fed with PP1.0. For serum indices, higher serum alkaline phosphatase (Alkp), phosphorus (P) and calcium (Ca) contents were observed in fish fed with phytase‐supplemented diets in comparison with the control. In addition, dietary phytase supplementation increased amylase activity and decreased lipase activity in both foregut and hindgut. The present study suggests that dietary MCP can be reduced when neutral phytase is added to the grass carp diet, and that the maximum MCP reduction level can be up to 1% when neutral phytase is supplemented at 500 FTU kg^?1 diet.     

Effect of Dietary Supplementation with Copper Sulfate or Tribasic Copper Chloride on the Growth Performance, Liver Copper Concentrations of Broilers Fed in Floor Pens, and Stabilities of Vitamin E and Phytase in Feeds

An experiment was conducted using a total of 840, 1-day-old, Arbor Acres commercial male broilers to compare copper (Cu) sulfate and tribasic Cu chloride (TBCC, Cu₂(OH)₃Cl) as sources of supplemental Cu for broilers fed in floor pens. Chicks were randomly allotted to one of seven treatments for six replicate pens of 20 birds each, and were fed a basal corn–soybean meal diet (10.20 mg/kg Cu) supplemented with 0, 100, 150, or 200 mg/kg Cu from either Cu sulfate or TBCC for 21 days. Chicks fed 200 mg/kg Cu as TBCC had a higher (P?<?0.05) average daily gain (ADG) than those consuming other diets. Liver Cu contents of broilers fed diets supplemented with TBCC were numerically lower (P?>?0.05) than those of broilers fed diets supplemented with Cu sulfate. The vitamin E contents and the phytase activities in the feed fortified with TBCC were higher (P?<?0.01) and numerically higher (P?>?0.05) compared with those in the feeds fortified with Cu sulfate stored at room temperature, respectively. The vitamin E contents in liver and plasma of broilers fed diets supplemented with TBCC were higher (P?<?0.05) than those of birds fed diets supplemented with Cu sulfate. This result indicates that TBCC is more effective than Cu sulfate in improving the growth of broilers fed in floor pens, and it is chemically less active than Cu sulfate in promoting the undesirable oxidation of vitamin E in feeds.     

Effect of diet composition and lysine supply on growth and body composition in juvenile turbot (Psetta maxima)

A 10-week feeding trial was conducted to study the effect of feeding level and dietary lysine concentration on growth, protein and lysine retention, and body composition in juvenile turbot. Maintenance requirement for lysine and the efficiency of lysine utilisation were determined as well. Two experimental diets were formulated based on fishmeal or wheat gluten as main protein sources, containing 6.4 g (Diet A, control) and 4.5 g lysine per 100 g CP (Diet B), respectively. Diets were fed once daily at six feeding levels (per day 0.3%, 0.6%, 0.9%, 1.2%, and 1.5% of body weight [BW] and ad libitum) to a total of 432 fish of 48 g initial BW. No differences in the growth parameters were observed between diets at the same feeding level, except a lower feed to gain ratio (p < 0.05) at the highest feeding level at Diet B. Whole-body composition was not affected by diet, whereas muscle protein concentration was significantly lower for fish fed Diet B. Amino acid concentration in whole-body protein was affected by dietary treatment and fish fed Diet B showed lower concentrations of all essential amino acids. In fish muscle protein, lysine, methionine, leucine, isoleucine, and valine concentrations were significantly lower in Diet B. Efficiency of lysine utilisation for growth (k_lys) was determined by linear regression analysis and amounted for 0.69 for Diet B. The maintenance lysine requirement defined at zero lysine retention was 6.5 mg · kg^?0.8 · d^?1. Lysine intakes at zero protein retention were 13.0 mg and 12.9 mg · kg^?0.8 · d^?1 for Diet A and B, respectively. Growth and nutrient retention were similar for both diets and, therefore, a lysine deficiency in Diet B did not occur. In conclusion, a proportion of 330 g wheat gluten per kg feed did not influence growth performance and maintenance requirement for lysine in juvenile turbot. However, the effect of diet composition on the amino acid profile of body protein might be relevant for the derivation of the amino acid requirement from protein retention.     

Dietary Administration of <Emphasis Type="Italic">Lactobacillus plantarum</Emphasis> Enhanced Growth Performance and Innate Immune Response of Siberian Sturgeon, <Emphasis Type="Italic">Acipenser baerii</Emphasis>

We investigated the effects of Lactobacillus plantarum used as a dietary supplement on the growth performance and innate immune response in juvenile Siberian sturgeon Acipenser baerii. Juvenile fish (14.6 ± 2.3 g) were fed three experimental diets prepared by supplementing a basal diet with L. plantarum at different concentrations [1 × 10⁷, 1 × 10⁸ and 1 × 10⁹ colony-forming units (cfu) g^?1] and a control (non-supplemented basal) diet for 8 weeks. Growth performance indices were increased in fish fed the 1 × 10⁸ cfu g^?1 L. plantarum diet compared to the other groups. There was an increased innate immune response in fish fed the experimental diets. The highest levels of lysozyme activity, total immunoglobulin (IgM) and complement component 3 (C3) were observed in fish fed the diet containing L. plantarum at a concentration of 1 × 10⁸ cfu g^?1, but there was no significant difference in the level of complement component 4 (C4) in fish fed the experimental diets or the control diet. The present study underlying some positive effects (growth performance and immune indices) of dietary administration of L. plantarum at a concentration of 1 × 10⁸ cfu g^?1 in the Siberian sturgeon.     

Involvement of Zn Depletion in Cd-Induced Toxicity on Prenatal Bone Formation in Rat

This experiment was conducted to evaluate the effects of chromium methionine with/without zinc sulfate or zinc amino acid complex on the growth performance, carcass traits, meat quality, serum parameters, endocrine parameters, and antioxidant status of growing-finishing pigs. A total of 180 (32.0 ± 1.7 kg body weight, BW) crossbred pigs (Duroc × Landrace × Yorkshire) were used in a completely randomized design with three dietary treatments and 10 replicates per treatment (five pens of barrows and five pens of gilts with six pigs per replicate). Three treatments were corn-soybean meal-based diets supplemented with 100 mg Zn/kg from zinc sulfate (ZnSO₄), 100 mg Zn/kg from ZnSO₄ + 0.2 mg Cr/kg from chromium methionine complex (CrMet), or 50 mg Zn/kg from ZnSO₄ + 50 mg Zn/kg from zinc amino acid complex (ZnAA) + 0.2 mg Cr/kg from CrMet, respectively. The experiment lasted 105 days, of which was divided into three stages including phase 1 (30 to 50 kg BW), phase 2 (50 to 80 kg BW), and phase 3 (80 to 110 kg BW). Results showed that supplementation with CrMet and ZnAA improved (P < 0.05) the feed conversion of the pigs in phase 2, phase 3, and the overall experiment. Hot carcass weight, dressing percentage, and a longissimus dorsi muscle area were increased (P < 0.05) in pigs fed with diets supplemented with both CrMet and ZnAA compared with pigs fed with diets containing only ZnSO₄ (P < 0.05). There was also an increase (P < 0.01) pH_24 h in the longissimus dorsi muscle in pigs fed with diets supplemented with CrMet and ZnAA. The concentration of serum glucose in pigs fed with diets containing CrMet and ZnAA was decreased (P < 0.05) compared with that in pigs fed with the diet containing ZnSO₄. Supplementation with CrMet and ZnAA increased (P < 0.05) the circulating levels of insulin and decreased (P < 0.05) cortisol. There was an increase (P < 0.05) in total serum antioxidant capacity and Cu/Zn superoxide dismutase activity as well as a decrease (P < 0.05) in serum malondialdehyde concentrations in pigs fed with diets supplemented with CrMet and ZnAA compared with pigs fed with the diet supplemented only with ZnSO₄. In conclusion, supplementation of CrMet only or CrMet together with ZnAA improved feed conversion, carcass traits, and meat quality in the growing-finishing pigs.     

Azadirachta indica (neem) leaf dietary effects on the immunity response and disease resistance of Asian seabass,Lates calcarifer challenged with Vibrio harveyi

The present study was aimed to address the possible evaluation of Azadirachta indica (neem) leaf-supplemented diets on innate immune response in Asian seabass, Lates calcarifer fingerlings against Vibrio harveyi infection. Fish were fed for two weeks diets containing six graded levels of neem leaf at 0 g, 1 g, 2 g, 3 g, 4 g and 5 g per kg feed. Fish fed neem leaf-supplemented diet displayed significant differences (p < 0.05) in weight gain, specific growth rate (SGR) and feed conversion ratio (FCR) compared to the control group fed without neem leaf-supplemented diet. Various innate immune parameters were examined pre-challenge and post-challenge. Fish was injected intraperitoneally with a lethal dose of V. harveyi containing 10⁸ cells mL^?1. Supplementation of neem leaf diet significantly increased phagocytic activity, superoxide anion production, serum lysozyme, serum bactericidal activity, serum anti-protease activity throughout the experimental period when compared with the control group. Dietary doses of neem leaf diet significantly influenced the immune parameters, haematological parameters and blood biochemical indices of treated fish. The results suggested that fish fed neem leaf-supplemented diet improved the immune system and increased survival rate in L. calcarifer fingerlings against V. harveyi infection.     

The Effect of Dietary Organic Chromium on Specific Growth Rate, Tissue Chromium Concentrations, Enzyme Activities and Histology in Common Carp, Cyprinus carpio L.

A 63-day feeding trial was carried out to investigate the effect of three levels of Cr yeast (0.5, 1.0 and 2.0?mg Cr/kg) on the utilization of diets containing 38.5?% of maize starch or dextrin in common carp, Cyprinus carpio L. (initial mean body mass 14?±?0.3?g) in an auto circulator system at 25?±?0.5?°C. A two-way analysis of variance (ANOVA) showed that the final body mass (FBM), percentage mass gain (%MG), specific growth rate (SGR) and feed conversion ratio (FCR) were significantly (P?<?0.05) affected by the two sources of variation (carbohydrate source and Cr level). In general, fish fed on a diet containing starch and fortified with 0.5?mg Cr/kg performed significantly higher FBM (47.23?g), %MG (225.11), SGR (1.91) and lower value of FCR (1.24) compared to fish fed on the other diets. Carp fed on 2.0?mg Cr/kg with maize starch and 1.0?mg Cr/kg with dextrin-based diet showed a significant reduction (P?<?0.05) in whole body lipid content as confirmed by a two-way ANOVA. Fish fed on a maize starch-based diet supplemented with 0.5 and 1.0?mg Cr/kg recorded the highest activities for hexokinase enzyme. Glucose-6-phosphate dehydrogenase activity was neither affected by Cr concentration nor by dietary carbohydrate source. Fish fed on dextrin-based diets accumulated higher Cr in the whole tissue compared to fish fed on starch-based diets. Normal histological structures in the liver and gut tissues were observed in all groups. The present data clearly showed that dietary Cr yeast was safe in the fish diet at the levels tested.     

Effects of dose and formulation of carvacrol and thymol on bacteria and some functional traits of the gut in piglets after weaning

Two trials were conducted to study the effects of dose and formulation of carvacrol and thymol on bacterial counts, metabolites and functional traits of the gut in weaned piglets. In the first experiment (Exp. I), 25 piglets (28 d, 6.59 ± 0.48 kg BW) were allocated to five dietary treatments: a control diet, or the same diet supplemented with either carvacrol or thymol at doses of 500 and 2000 mg kg^?1. In the second experiment (Exp. II), 35 piglets (28 d, 7.99 ± 0.73 kg BW) were assigned to seven dietary treatments: the same control diet as in Exp. I, or this diet supplemented with thymol in one of three formulations (on celite, on alphacel or microencapsulated) at doses of 500 and 2000 mg kg^?1. At 11/12 days post-weaning piglets were euthanised, and digesta from stomach, proximal and distal small intestine were sampled for bacteriological and biochemical analysis. Small intestinal tissue was sampled for histo-morphological determinations. In none of the experiments or sections of the gut was the number of bacteria lowered by the carvacrol or thymol supplementation. In Exp. I, the villus/crypt ratio at the distal small intestine for the experimental diets (1.30–1.32) was higher than for the control diet (1.24) (p < 0.05). Thymol fed animals in Exp. II had a lower number of intra-epithelial lymphocytes at the proximal (p < 0.05) and at the distal (p < 0.1) small intestine as compared to control animals. Mean concentration of the active ingredient in the stomach and proximal small intestine for the 2000 mg kg^?1 carvacrol diet was 521 and 5 mg kg^?1 fresh digesta, respectively, and for the 2000 mg kg^?1 thymol diets it ranged between 475 and 647 and between 13 and 24 mg kg^?1 fresh digesta, respectively. Cumulative absorption in the proximal small intestine was higher than 90% for all treatments and was not affected by formulation type. These data suggest that carvacrol and thymol can improve gut health, but evidence for clear antimicrobial effects towards the major culturable bacteria of the pig foregut is limited.     

Effect of feeding different protein to energy (P/E) ratios on the growth performance and body composition of Oreochromis niloticus fingerlings

This study evaluated the growth performance and body composition of Oreochromis niloticus fingerlings (average initial weight 16.53 ± 0.44 g) fed 9 experimental diets (A, B, C, D, E, F, G, H and I) containing three different levels of protein (26, 31 and 36 g 100 g^?1) at three different gross energy (GE) levels (16, 19 and 22 MJ kg^?1) for a period of 64 days. Significant differences were observed in the feed consumption, body weight gain, specific growth rate (SGR), condition factor (k), feed conversion ratio (FCR), protein efficiency ratio (PER), net protein retention (NPR) and apparent net energy retention (ANER) values of fish when the energy level of diet was increased at different protein levels. The maximum weight gain, SGR and k were observed on diet F containing 36% protein and an energy level of 19 MJ kg^?1 of dry feed with a protein to energy (P/E) ratio of 18.96 (g protein MJ^?1 GE). A further increase in the energy content of the diet (22 MJ kg^?1) at the same protein level (Diet I) did not produce any improvement in the growth performance. Lowering the energy level at the same protein level significantly affected the growth performance. Fish fed diet B containing 31% protein and a lower energy level of 16 MJ kg^?1 with the same P/E ratio of 18.61 as diet F showed significantly lower weight gain and growth performance than diet F. Diets E and H containing 31% crude protein at all three energy levels produced similar results as diet B. The poorest FCR was observed when the diet contained both lower levels of protein and energy. Fish fed diet G, containing 26% protein at high energy level (22 MJ kg^?1), showed the best PER and NPR values. The PER and NPR were the poorest on diet C containing 36% protein at low energy level (16 MJ kg^?1). The body moisture content at all protein levels decreased (P < 0.05) with the increasing level of dietary energy whereas the body fat content increased (P < 0.05). Similar trends were observed in the body ash and energy content. Increasing the dietary energy content at lower protein levels did not show any difference (P > 0.05) in body protein content. Our results indicated the optimum P/E ratio for O. niloticus as 18.96 g protein per mega joule of gross energy at 36% dietary protein level and a dietary gross energy value of 19 MJ kg^?1.