Effects of dietary oleuropein supplementation on growth performance,serum lipid concentrations and lipid oxidation of Japanese quails

An in vivo experiment was conducted to compare the effects of dietary supplementation with oleuropein and/or α‐tocopheryl acetate on growth performance, serum lipid concentrations and lipid oxidation of Japanese quail meat during refrigerated storage. Performance and slaughtering parameters were not affected by dietary treatments. The diets supplemented with oleuropein at the levels of 150 or 200 mg/kg were more effective in delaying lipid oxidation in breast and thigh meats compared with the control diet. The dietary inclusion of neither vitamin E nor oleuropein at different levels did not significantly affect the fatty acid compositions of the breast meat compared with the control diet. The diets supplemented with oleuropein at the levels of 150 or 200 mg/kg had significantly the highest polyunsaturated fatty acid and omega‐3 fatty acid contents in thigh meat compared with the vitamin E diet. The ratio of omega‐6 fatty acids to omega‐3 FAs in thigh meat of quails fed diet supplemented with vitamin E at the level of 200 mg/kg was equivalent to those of quails fed the diets supplemented with oleuropein at the levels of 100 and 150 mg/kg . The results showed that the dietary oleuropein supplementation at 150 mg/kg level may be used in quail diets enriched with the polyunsaturated fatty acids of vitamin E as a natural antioxidant.     

Dietary lutein and fish oil interact to alter atherosclerotic lesions in a Japanese quail model of atherosclerosis

Interactions between concentration of dietary lutein and fish oil in diets on atherosclerosis incidences were studied in a cholesterol-induced-atherosclerosis (CIA) model. CIA Japanese quail were fed a basal diet with three amounts of lutein (0, 25 and 50 mg/kg diet) and two amounts of fish oil (3% and 6%) in a 3 × 2 factorial in five replications. Samples were collected at 24 and 27 weeks of age. Atherosclerosis lesions in the dorsal aorta were measured by histochemistry sectioning. At 27 weeks of age, increasing dietary fish oil content to 6% decreased (p < 0.01) the atherosclerotic lesions only in the 0 mg lutein supplemented groups. At 27 weeks of age, increasing dietary fish oil content to 6% increased the atherosclerotic lesion score when lutein was supplemented at either 25 or 50 mg/kg feed. Aorta and liver lutein content increased (p < 0.01) with increasing dietary lutein content at 27 weeks of age. Increasing dietary fish oil content to 6% increased (p < 0.01) the aorta fat content by twofold and decreased (p < 0.01) the liver fat by 26% at 27 weeks of age. Increasing the dietary fish oil content to 6% increased (p = 0.01) the total PUFA and decreased (p = 0.03) the total mono unsaturated fatty acids content of the aorta at 27 weeks of age. At 27 weeks of age, increasing dietary fish oil content to 6% decreased the amount of TBARS (p = 0.01) and IL-1 mRNA (p < 0.01) only in the 0 mg lutein supplemented groups. Increasing dietary fish oil content to 6% increased the amount of TBARS and IL-1 mRNA of the aorta when lutein was supplemented at either 25 or 50 mg/kg diet. Dietary lutein supplementation decreased atherosclerosis lesions only at low levels of dietary polyunsaturated fatty acids.     

Effects of dietary lysozyme levels on growth performance,intestinal morphology,non‐specific immunity and mRNA expression in weanling piglets

The aim of the present study was to determine the effect of dietary lysozyme levels on growth performance, gut health and non‐specific immunity of weanling piglets. A total of 150 weanling piglets were allocated to six treatments. The piglets were fed the same basel diet supplemented with 0, 30, 60, 90 and 120 mg/kg lysozyme as well as antibiotics for 28 days. From day 14 to day 28 of dietary treatment, piglets fed 90 mg/kg lysozyme had greater average daily gain than piglets fed control diet. During the whole experimental period, piglets fed 120 mg/kg lysozyme tended to have greater average daily gain than piglets fed control diet. Compared with piglets fed control diet, piglets fed diets containing antibiotics and 90 mg/kg lysozyme had greater villus height to crypt depth ratio in duodenum and jejunum. Additionally, dietary supplementation of 60 and 90 mg/kg lysozyme as well as antibiotics enhanced the phagocytic activity of peritoneal macrophages in piglets. In conclusion, dietary lysozyme can accelerate the growth of weanling piglets by improving gut health and non‐specific immunity and supplementing 90 mg/kg lysozyme is as effective as antibiotics (20 mg/kg colistin sulphate + 50 mg/kg kitasamycin) in improving the growth performance of weanling piglets.     

Dietary Ascorbyl Monophosphate Depresses Lipid Peroxidation in Rainbow Trout Spermatozoa

Abstract

This study was designed to analyze lipid peroxidation in spermatozoa of rainbow trout Oncorhynchus mykiss by an optimized thiobarbituric acid (TBA) method, and to evaluate the effect of graded levels of dietary antioxidant (ascorbic acid in the form of ascorbyl monophosphate, AP) on TBA values of spermatozoa. Sperm from rainbow trout fed diets supplemented with AP at 0, 110, or 870 mg/kg were sampled during the reproductive season. The group given the unsupplemented diet had the lowest ascorbic acid concentration in seminal plasma during most of the spermiation season compared with groups fed diets with AP While the ascorbic acid concentration in seminal plasma decreased toward the end of the reproductive season, spermatozoa malondialdehyde production, indicative of increasing peroxidation, tended to increase. At the end of the season, significant differences (P < 0.05) were found in peroxidation levels in spermatozoa from fish fed different levels of ascorbic acid. The most abundant polyunsaturated fatty acid in sperm lipids, docosahexaenoic acid (C22:6), was significantly lower in lipids from spermatozoa of the AP-devoid (control) group than in the 870-mg/kg supplement group. By the end of the reproductive season, spermatozoa from the control group had significantly higher peroxidation levels than did spermatozoa from fish given AP (110 and 870 mg/kg). Thus, it is the first evidence in fish that dietary AP supplements can increase seminal plasma ascorbic acid concentrations, and it suggests that peroxidative damage to spermatozoa can be reduced during the reproductive season, which in turn may affect sperm fertilizing ability.     

Effects of Dietary Zinc and Calcium on Select Immune Functions of Channel Catfish

Abstract

The effects of dietary zinc and calcium on immunocompetence of channel catfish Ictalurus punctatus (mean initial weight = 3.1 g/fish) were determined after a 10-week feeding trial. Fish were fed daily amounts equal to 3% of their body weight of one of six purified diets that were deficient in zinc (2 mg/kg of diet), calcium (0.02% of diet), or both; replete with zinc (20 mg/kg of diet) and calcium (0.5% of diet); or excessive in zinc (200 mg/kg of diet) or calcium (2.5% of diet). Immunocompetence of immunized and nonimmunized fish fed the various diets was assessed by measuring serum immunoglobulin M levels and mortality after an intraperitoneal injection of live Aeromonas hydrophila. Channel catfish fed diets deficient in zinc, calcium, or both had significantly (P ≤ 0.05) less weight gain and survival as compared with those fed diets replete with or excessive in zinc or calcium. Tissue mineral concentrations of fish indicated that various levels of zinc and calcium nutriture existed when immune functions were tested. Diet affected mortality of only nonimmunized fish in the bacterial-challenge test; zinc deficiency and calcium excess decreased mortality. Whereas growth and survival of fish were reduced by dietary zinc or calcium deficiency, the measured immunological characteristics were not equally impaired by these mineral deficiencies.     

Effect of Dietary Vitamin E on Cortisol and Glucose Responses to Handling Stress in Juvenile Beluga Huso huso

Abstract

An 8-week feeding experiment was conducted to investigate the effect of dietary vitamin E on the physiological response to handling stress in juvenile beluga Huso huso. Fish were fed six experimental diets supplemented with 0, 25, 50, 100, 200, or 400 mg Dl-all-rac-α-tocopherol acetate/kg diet. At the end of the experiment, the fish in each tank were subjected to acute handling and air exposure stress. Cortisol and glucose were measured as the primary hormonal and secondary metabolic responses to the stressors, both before and 3 h after application of the stressors. The growth parameters and feed utilization rates were significantly lower in fish fed the diet not supplemented with vitamin E than in fish fed diets supplemented with vitamin E. Cortisol concentration was not affected by dietary treatment but glucose concentration was. Fish fed vitamin E at 0, 25, 100, and 400 mg/kg diet had higher concentrations of glucose than those fed vitamin E at 50 and 200 mg/kg. However, fish fed diets with 50 and 200 mg/kg exhibited higher growth rates. These results indicate that dietary vitamin E has some effect on plasma glucose but no effect on plasma cortisol. In general, when the stressors were applied to belugas, the glucose and cortisol responses were relatively low. This may be due to higher resistance and lower physiological responses to these types of stressors by this species or by chondrosteans in general.

Received January 10, 2011; accepted August 4, 2011     

Pre-treatment of dietary plant feedstuffs with phytase and its effect on growth and mineral concentration in common carp (Cyprinus carpio L.)

Effect of phytase pre-treatment of dietary plant feed stuffs (PF) on growth and mineral concentration in common carp (C. carpio L.) was investigated. Diets used were: C0, diet with no supplement; CI, diet with incubated PF; CP0, diet supplemented with 3 g P/kg; CPI, diet with incubated PF supplemented with 3 g P/kg; Phyt0, diet fortified with 4000 U phytase/kg; PhytI, diet with PF incubated with 4000 U phytase/kg. Mean weight gain, SGR and FCR were the same (p < 0.05) in fish fed CP0, CPI or PhytI but less (p < 0.05) in other fish. Bone P was similar in fish fed CP0 (74.9), CPI (75.9) or PhytI (71.5 mg/g DM) but higher (p < 0.05) than in fish fed C0. Bone Ca and Mg were similar in fish fed CP0, CPI or PhytI but less (p < 0.05) in other fish. Bone Zn in fish fed C0, Phyt0 or PhytI was higher (p < 0.05) than that in fish fed CP0 or CPI. In conclusion, CP0, CPI and PhytI had the same effect, suggesting phytase pre-treatment as the most effective method. CPI did not have any advantage over CP0. Phytase increased mineral availability and utilization, which would minimize cost of mineral supplementation and discharges into the environment.     

Immune Response and Resistance of Channel Catfish to Edwardsiella ictaluri Challenge when Fed Various Dietary Levels of Zinc Methionine and Zinc Sulfate

Abstract

The effects of dietary levels of zinc from zinc methionine (ZnM) and zinc sulfate ZnSO₄ on nonspecific immune responses and disease resistance of juvenile channel catfish Ictalurus punctatus (mean initial weight of 3.3 g) were determined. Fish in triplicate aquaria were fed to satiation twice daily for 16 weeks with an egg white basal diet without zinc supplementation or supplemented with 5, 20, and 60 mg zinc/kg as ZnM or 20 and 60 mg zinc/kg as ZnSO₄. Relative percentages of peripheral blood lymphocytes, thrombocytes, and macrophages were not affected by dietary zinc. The relative percentages of neutrophils significantly increased in fish fed 20 and 60 mg Zn/kg as ZnM. Chemotactic responses of macrophages were significantly higher for fish fed the three ZnM-supplemented diets and the 60-mg ZnSO₄. Dietary zinc, however, had no influence on the phagocytic activity of macrophages for Edwardsiella ictaluri. Likewise, neither the source nor the level of dietary zinc provided protection to channel catfish against E. ictaluri. The severity of E. ictaluri infection (number of colony-forming units/g trunk kidney) and the percentage offish that were culture negative for E. ictaluri (15 d postchallenge) were also unaffected by dietary zinc.     

Influence of Dietary Ascorbic Acid on the Immune Responses of Juvenile Korean Rockfish Sebastes schlegelii

Juvenile Korean Rockfish Sebastes schlegelii (length, 13.6 ± 1.4 cm [mean ± SD]; weight, 53.6 ± 4.2 g) were fed twice daily with diets containing varying levels of ascorbic acid (0, 50, 100, 200, and 400 mg/kg) for 4 weeks. Significant increases in daily weight and length occurred in fish fed more than 50 mg/kg ascorbic acid. The lysozyme activity of fish fed diets containing ascorbic acid was considerably increased in rockfish plasma at 400 mg/kg ascorbic acid and in kidney at over 50 mg/kg ascorbic acid. Total plasma immunoglobulin M (IgM) levels were markedly elevated in fish fed 400 mg/kg ascorbic acid. The results suggest that dietary ascorbic acid supplementation in juvenile rockfish can induce a significant increase in growth and in immunological features such as lysozyme activity and plasma IgM levels.

Received October 1, 2014; accepted May 2, 2015     

The effects of withdrawal of vitamin and trace mineral supplements from layer diets on egg yield and trace mineral composition

1. This study was conducted as three trials. 2. In the first trial, zinc, manganese, copper and iron concentrations were determined in dietary raw materials collected from various regions of Turkey. 3. In the second trial, 200 Hisex Brown laying hens, 30 weeks of age, were divided into two groups. The first group served as controls and were fed on a standard commercial layer diet. The second group were fed on a commercial layer diet that was not supplemented with trace minerals and vitamins. Egg production, egg weight, specific gravity, food consumption and food efficiency of the birds in each group were determined. In the unsupplemented group, egg production (0.75 vs 0.83) and food intake (114 vs 122 g) were lower than the those of the control group (P < 0.05). Food efficiency was 2.42 (kg food/kg gain) in the group consuming the unsupplemented diet and 2.36 in the controls. 4. In the third trial, as in Trial 2, Hisex Brown laying hens, 62 weeks of age were used. In the unsupplemented group, the mean egg weight was significantly lower than that of controls (68.0 vs 69.6 g) (P < 0.01). 5. At the end of the second and third trials, egg samples collected from experimental groups were hard boiled in water. The levels of zinc, manganese, copper and iron in the egg yolk were determined. The zinc level of the egg yolk from the control group of second trial was higher (23.5 mg/kg) than those of the unsupplemented group (13.6 mg/kg).     

The influence of dietary boron supplementation on egg quality and serum calcium, inorganic phosphorus, magnesium levels and alkaline phosphatase activity in laying hens

This study was performed to investigate the influence of dietary boron (B) supplementation on egg production, interior and exterior egg quality and serum parameters related to egg formation in laying hens. Two hundred and twenty four, 18 week old, Hyline Brown 98 strain hens were assigned to 7 groups with 4 replicates. After 10 days of adaptation the hens were fed for 8 weeks on diets supplemented with 0, 5, 10, 50, 100, 200 and 400 mg/kg (diet) B (H₃BO₃). Live weight, feed consumption and egg production were reduced in the 400 mg/kg B supplemented group. Increases were determined in serum Ca, inorganic P and Mg levels and serum ALP activity was not influenced by supplemental B. Boron changed the interior and exterior quality of eggs. In particular, high level of B supplementation reduced live weight, feed consumption and egg production and changed some blood metabolites.     

Immunomodulation by dietary vitamin C in healthy and aflatoxin B1-induced immunocompromised rohu (Labeo rohita)

The aim of this study was to examine the immunomodulatory effect of high levels of dietary vitamin C in healthy and immunocompromised rohu (Labeo rohita) treated with aflatoxin B1 (AFB1). Four groups of rohu were fed experimental diets containing either no vitamin C or supplemented with vitamin C at 500 ppm for 60 days. On the first day of feeding, one group fed the high vitamin C diet and one fed the vitamin C deficient diet, were injected intraperitoneally with a single doses of AFB1 at 1.25 mg kg(-1) body weight. The effect of AFB1 and high dietary vitamin C on specific and non-specific immunity, and disease resistance against Aeromonas hydrophila were examined in the rohu. The ability of vitamin C to counteract immunosuppression induced by AFB1 was also examined. Specific immunity indicated by haemagglutination and haemolysin titres against sheep red blood cells (SRBC), and bacterial agglutination appeared to be unaffected by either the AFB1 treatment or the vitamin C enriched diet. A significant reduction was observed in the non-specific immunity of AFB1-treated fish, however, indicated by lowered bactericidal and lysozyme activities. High dietary vitamin C, on the other hand, enhanced the non-specific immunity of fish, including an enhanced phagocytic ratio and increased serum lysozyme activity. Feeding a high level of dietary vitamin C to AFB1-treated fish increased these parameters to levels similar to those found in control fish. High dietary vitamin C significantly (p < 0.05) enhanced protection against Aeromonas hydrophila infection in both healthy and immunocompromised fish. Results from this study help to establish the beneficial effect of dietary vitamin C on AFB1-induced immunosuppression, as well as confirming the immunostimulatory effect of vitamin C in rohu.     

Effect of Vitamin E on the Immune Response of Channel Catfish to Edwardsiella ictaluri

Abstract

Three-month-old fingerling channel catfish Ictalurus punctatus were fed purified diets supplemented with ∝-tocopherol acetate to provide 0, 60, and 2,500 mg vitamin E/kg for 180 d. A 30-s immersion bath and an oral booster were used to deliver a bacterin of formalin-killed Edwardsiella ictaluri to half of the fish from each dietary treatment. Resistance of red blood cells to peroxidation was used as an index of antioxidant status. The susceptibility of red blood cells to oxidative hemolysis decreased with increasing levels of dietary vitamin E. Vaccinated and nonvaccinated fish were evaluated for agglutinating antibody titers and macrophage activity. Humoral antibody titers in response to E. ictaluri were significantly (P ≤ 0.05) higher in vaccinated fish than in nonvaccinated fish; however, no such differences in agglutinating antibody titers were detected among any of the dietary treatment groups. Both vaccination and vitamin E significantly enhanced the ability of macrophages to phagocytize virulent E. ictaluri. Results of this study indicate that elevated levels of dietary vitamin E may affect the ability of channel catfish to respond immunologically to bacterial pathogens.     

The effects of dietary calcium iodate on productive performance,egg quality and iodine accumulation in eggs of laying hens

The aim of this study was to examine the effects of various levels of supplemental calcium iodate (CI) on productive performance, egg quality, blood indices and iodine (I) accumulation in the eggs in commercial laying hens. A total of 240 White Leghorn layers (Hy‐line W36) were divided through a completely randomized design into six treatments with five replicates and eight hens per each at 32 weeks of age. This experiment lasted for 12 weeks. Concentrations of I in the mash diets were 0.74, 3.13, 5.57, 8.11, 10.65 and 12.94 mg I/kg of feed in treatments 1–6 respectively. The added doses of CI were included 0.0 (control), 2.5, 5.0, 7.5, 10.0 and 12.5 mg/kg of diet for treatments 1–6 respectively. There were no significant differences in productive performance among the treatments. The highest eggshell strength was observed in group fed diet containing 3.13 mg I/kg (p = .014). The highest percentage of calcium and lowest percentage of phosphorus in eggshell were observed in group fed diet containing 12.94 mg I/kg (p = .0001). Feeding hens with diet containing 12.94 mg I/kg increased serum triiodothyronine‐to‐thyroxine ratio (p = .0001). Serum alanine aminotransferase activity in hens fed diet containing 12.94 mg I/kg was significantly more than control (p = .041). Blood Serum triglycerides in hens fed diet containing 8.11 mg I/kg were significantly higher than control (p = .0001). Edible fraction of the eggs of birds fed diet containing 12.94 mg I/kg was enriched by I almost 3 times more than those fed diet containing 0.74 mg I/kg. The results suggested that egg production, egg mass, feed intake and feed conversion ratio were not significantly affected by dietary I levels. Iodine accumulation in the eggs were increased by increasing dietary I levels and the level of 10 mg/kg CI could supply I enrichment of the eggs.     

Effect of Long‐term Oral Administration of an Immunostimulant Diet on Innate Immunity in Sea Bass (Dicentrarchus labrax)

Immunostimulants represent a modern and promising tool in aquaculture, enhancing the resistance of cultured fish to disease and stress. This study investigated the effect of a combination of dietary glucans, α‐tocopherol and ascorbic acid on the innate immune response of cultured sea bass (Dicentrarchus labrax). After 5 weeks of adaptation on a commercial diet containing 100 p.p.m. ascorbic acid and 200 p.p.m. α‐tocopherol, sea bass were switched to a diet supplemented with 2% β?1.3/β?1.6 glucans and ascorbic acid and α‐tocopherol at 500 p.p.m. The supplemented diet was given at 2% of body weight per day over a 2‐week period, every 3 months. Plasma lysozyme concentration, content and distribution of major plasma proteins and complement activity were measured prior to feeding the supplemented diet and after 40 weeks. Alternative pathways of complement activation and lysozyme activity were both significantly enhanced in fish fed on glucans and elevated doses of vitamins. No significant differences were observed in protein content or in albumin/globulin ratio. Compared to lysozyme activity, which showed marked individual variation, complement‐mediated haemolytic activity has been shown to be a more reliable indicator of sea bass immunocompetence. Further studies are in progress to clarify the effect of each dietary component on the innate immune response and disease resistance.     

Hypocholesterolemic effect of karaya saponin in Japanese laying quails (Coturnix coturnix japonica)

The effect of karaya saponin supplementation on the serum and egg yolk cholesterol and fatty acid composition in egg yolk were investigated in Japanese quails. A total of 80 Japanese quails aged 5 weeks were equally divided into four groups of 20. Four levels (0, 25, 50 and 75 mg/kg feed) of karaya saponin were included in the basal diet and experiment was lasted for 6 weeks. The cholesterol fractions in the egg yolk and serum were measured by enzymatic assay, and the fatty acid composition in egg yolk was determined by gas chromatography. The results revealed that the supplementation of 75 mg/kg karaya saponin significantly reduced (p < 0.05) cholesterol and triglycerides concentration in serum and egg yolk. High-density lipoprotein-cholesterol was increased, low-density lipoprotein-cholesterol and the atherogenic index were decreased (p < 0.05) by the dietary supplementations. Hepatic cholesterol was reduced (p < 0.05) by the 25 mg/kg karaya saponin. A higher degree of yolk colour was improved (p < 0.05) when 75 mg/kg saponin was supplemented in the diet. The concentration of polyunsaturated fatty acids (PUFA) in egg yolk was increased (p < 0.05) in a dose-dependent manner in quails fed the supplemented diet than the control diet. The ratio of PUFA to saturated fatty acids in egg yolk was improved (p < 0.05) by 75 mg/kg feed karaya saponin-supplemented diet. Therefore, the dietary supplementation of 75 mg/kg karaya saponin may be a feasible means of producing quail eggs with lower cholesterol and higher PUFA content for health conscious consumers.     

Effects of dietary supplementation of selenium and iodine on growth performance,carcass characteristics and histology of thyroid gland in goats

This study assessed the effects of dietary selenium (Se), iodine (I) and a combination of both on growth performance, thyroid gland activity, carcass characteristics and the concentration of iodine and selenium in Longissimus lumborum (LL) muscle in goats. Twenty‐four bucks were randomly assigned to four dietary treatments: control (CON), basal diet without supplementation, basal diet + 0.6 mg Se/kg dry matter (DM) (SS), 0.6 mg I/kg DM (IP), or combination of 0.6 mg/kg DM Se and 0.6 mg/kg DM I (SSIP) and fed for 100 days. Animals fed diet SSIP exhibited higher (P < 0.05) body weight and better feed conversion ratio (FCR) than those fed other diets. Dressing percentage of goats fed the supplemented diets was higher (P < 0.05) than that of the control. Carcasses from the IP group had higher (P < 0.05) total fat proportion than the SSIP group. The levels of both elements were significantly elevated (P < 0.05) in LL muscle in supplemented goats. Thyroid follicular epithelial cells of IP and SSIP animals were significantly higher than those of CON and SS groups. The study demonstrated that the combined Se and I dietary supplementation improves growth performance, carcass dressing percentage and increases the retention of Se and I in goat meat.     

Effect of dietary supplementation of organic zinc on laying performance,egg quality and some biochemical parameters of laying hens

This study was conducted to evaluate the effects of zinc methionine (Zn‐Met) supplementation on the performance, egg quality, antioxidant status and some biochemical parameters of blood serum in laying hens from 22 to 34 weeks of age. A total of 120 Hisex Brown laying hens of 22‐week‐old were randomly allocated into five treatments with six cage replicates for each (four hens/replicate). Dietary treatments consisted of the basal diet with no Zn‐Met supplementation (control group) and basal diet supplemented with 25, 50, 75 or 100 mg Zn‐Met/kg diet. No significant differences were observed on body weight, body weight gain or feed conversion ratio due to dietary Zn‐Met supplementation. However, highly significant impact was observed on daily feed intake. Egg number, egg weight and egg mass were increased in the group fed diet supplemented with the highest level of Zn‐Met (100 mg/kg of diet) as compared to other groups. All egg quality traits were statistically (p > .05 or .01) affected as a response to dietary Zn‐Met supplementation except egg shape index, shell percentage and yolk index. In comparison with the control group, dietary supplementation of 25, 50, 75 or 100 mg Zn‐Met/kg decreased serum triglyceride and LDL‐cholesterol levels. Serum cholesterol level was increased with all dietary levels of Zn‐Met in comparison with the control group. Dietary Zn‐Met supplementation increased the serum content of zinc, where the highest values were recorded with 50 and 100 mg Zn‐Met/kg diet. Dietary Zn‐Met levels did not affect the antioxidant indices in blood serum except for the activity of copper–zinc superoxide dismutase (Cu‐Zn‐SOD). The activity of Cu‐Zn‐SOD was increased with Zn‐Met supplementations with no differences among supplemental zinc levels. It is concluded that dietary Zn‐Met supplementation reduced serum triglyceride, LDL‐cholesterol and increased Zn status and resulted in promoting antioxidant ability of laying hens, and the addition of 100 mg Zn‐Met/kg to layer diet was appropriate for improving the above parameters in addition to egg production indices and Haugh unit score.     

Effects of replacing a dietary antibacterial agent (zinc bacitracin) with copper salts in Cherry Valley Pekin meat ducks

1. A study was conducted to investigate the effectiveness of high dietary copper concentrations obtained from tribasic copper chloride (TBCC, 58% copper) and copper sulphate pentahydrate (CuSO₄, 25% copper) in replacing antibiotic growth promoters (AGP) in duck diets.

2. A total of 960 one-day-old Cherry Valley meat-strain ducks were divided into 3 treatment groups, with 8 replicates per treatment, in a 6-week feeding trial. The ducks were fed a basal diet supplemented with AGP (40?mg zinc bacitracin/kg and 40?mg garlicin/kg of diet) or 150?mg of Cu/kg of diet, given as either CuSO₄ or TBCC.

3. The body weight, average daily gain, average daily feed intake and mortality of ducks were not affected by the dietary treatments. However, the feed/gain ratio of ducks that were fed TBCC diets was significantly lower than those of ducks that were fed CuSO₄ diets and were similar to those in the AGP group.

4. TBCC increased the Cu content in the liver tissue of ducks compared with the content in those that were fed the diet supplemented with AGP. TBCC also increased the Fe and Zn content in breast muscles compared with that in ducks that were fed the diet supplemented with CuSO₄.

5. The activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) were significantly higher in the serum of ducks that received the diet supplemented with TBCC than AGP or CuSO₄. TBCC treatment decreased the malondialdehyde (MDA) content in serum of ducks compared with groups supplemented with CuSO₄.

6. No significant difference was observed in liver or muscle fat content among the different dietary treatment groups. The serum low-density lipoprotein cholesterol concentration was lower in ducks fed AGP diets than those fed CuSO₄ diets.

7. It was concluded that the replacement of AGP with 150?mg of Cu/kg of feed from TBCC improved the feed efficiency, trace mineral deposition and antioxidant status more than when the source of copper was CuSO₄.     

Experimental Treatment of Aeromonas salmonicida Infections with Enrofloxacin and Oxolinic Acid: Field Trails

Abstract

The antimicrobials enrofloxacin and oxolinic acid were evaluated under field conditions for treatment of clinical Aeromonas salmonicida infections in salmonids by feeding medicated diets. Treatment of Atlantic salmon Salmo salar with enrofloxacin or oxolinic acid at 5 mg/ kg per day for 5 d was not successful. Monitoring of enrofloxacin-medicated fish revealed low tissue and serum antimicrobial activities. Lack of efficacy in the Atlantic salmon trial may have been due to the low dose, lack of bioavailability of the drug, or lack of acceptance of the medicated ration. Treatment of hybrid brook trout Salvelinus fontinalis × lake trout S. namaycush was successful when enrofloxacin was used at 10 mg/kg per day for 10 d, but not when oxolinic acid was used at 5mg/kg per day for 10 d. Antimicrobial activity in tissues of enrofloxacin-medicated fish was elevated during the 10-d treatment period. No antimicrobial activity could be detected in muscle, skin, or liver of the enrofloxacin-medicated fish at 20 d after the last day of medication.