Oral administration of yeast, Saccharomyces cerevisiae, enhances the cellular innate immune response of gilthead seabream (Sparus aurata L.)

The effects of including lyophilised whole yeast, Saccharomyces cerevisiae, in the diet on the seabream innate immune response were investigated. Gilthead seabream (Sparus aurata L.) specimens were fed four different diets for 4 weeks: a commercial diet as control and the same diet supplemented with 1, 5 or 10 g/kg yeast. After 1, 2 and 4 weeks, serum complement titres, as a humoral parameter, and phagocytic, respiratory burst, myeloperoxidase and natural cytotoxic activities of head-kidney leucocytes, as cellular parameters, were evaluated. The results showed that yeast supplements enhanced all the latter responses, but not the humoral response. This enhancement was dose-dependent except for the cytotoxic activity that was only stimulated by the lower dose of yeast assayed. As yeast cell walls are able to enhance the seabream cellular innate immune response, these results support the possible use of whole yeast as natural inmunostimulants in common fish diets.     

Effect of oral administration of high vitamin C and E dosages on the gilthead seabream (Sparus aurata L.) innate immune system

The effect of the oral administration of high dosages of vitamins C and E on the innate immune system of the seabream was investigated. Gilthead seabream (Sparus aurata L.) were fed four different diets for 45 days: a commercial diet as control, a 3g/kg vitamin C-supplemented diet, a 1.2g/kg vitamin E-supplemented diet or a diet containing both vitamin supplements. After 15, 30 and 45 days, serum ascorbic acid and alpha-tocopherol levels, growth, complement titers and head-kidney leucocyte phagocytic and respiratory burst activities were evaluated. The results showed that serum vitamin levels reflected dietary input. Fish fed the vitamin C-supplemented diet showed an enhanced respiratory burst activity, while fish fed the vitamin E-supplemented diet exhibited increased complement and phagocytic activities. All of these positive effects were found in fish fed the joint diet, as well as a synergistically enhanced respiratory burst activity at day 30. The results demonstrate that in vivo vitamins C and E exert a synergistic effect enhancing the respiratory burst activity of seabream phagocytes.     

Dietary administration of sodium alginate and kappa-carrageenan enhances the innate immune response of brown-marbled grouper Epinephelus fuscoguttatus and its resistance against Vibrio alginolyticus

Brown-marbled grouper Epinephelus fuscoguttatus which had been fed diets containing sodium alginate and kappa (kappa)-carrageenan at 5, 10 and 20gkg(-1), respectively after 0, 2, 4, 6, 8 and 14 weeks were examined for survival, growth, innate cellular and humoral responses as compared to the fish that fed control non-supplemented diet. Survival was 100% for the fish that fed all diets after 14 weeks and no significant difference in growth was observed among seven diets. The fish that fed a diet containing sodium alginate at 10gkg(-1), and fed a diet containing kappa-carrageenan at 5gkg(-1) over 2-8 weeks showed significantly increased leucocyte count, respiratory burst, phagocytic activity and phagocytic index, The fish that fed a diet containing sodium alginate at 5gkg(-1), and fed a diet containing kappa-carrageenan at 5gkg(-1) over 2-8 weeks showed significantly increased alternative complement activity (ACH50) and lysozyme activity. In another experiment, E. fuscoguttatus, which had been fed control diet, and all diets containing sodium alginate, and kappa-carrageenan after 14 weeks were challenged with Vibrio alginolyticus at 5.0x10(9) colony-forming units (cfu) fish(-1) and then placed in seawater of 34 per thousand. The survival of fish that fed a diet containing sodium alginate at 10gkg(-1) and kappa-carrageenan at 5gkg(-1) was significantly higher than that of fish which fed the control diet over 96-168h. It was concluded that E. fuscoguttatus which fed a diet containing sodium alginate at 10gkg(-1) or less, or fed a diet containing kappa-carrageenan at 5gkg(-1) enhance the innate immunity, and increase the resistance from V. alginolyticus infection.     

Total serum immunoglobulin M levels are affected by immunomodulators in seabream (Sparus aurata L.)

Immunoglobulin M (IgM) is a major component of the teleost humoral immune system. Despite the significance of IgM levels as an immune parameter, there are relatively few studies on changes induced in its total levels in serum. This study examines the effects of several immunomodulators (vitamin A, chitin, yeast cells or levamisole, which act as immunostimulants, and crowding, hypoxia or anaesthetics, which act as stressors) upon the total serum IgM levels of non-immunized gilthead seabream (Sparus aurata L.). Total serum IgM levels of fish fed with the assayed immunostimulant-supplemented diets were statistically higher than those in fish fed a non-supplemented diet, especially in the case of levamisole. On the other hand, serum IgM levels of fish subjected to different stressors were not affected by crowding, hypoxia or certain anaesthetics. However, benzocaine and a narcotic dose of 2-phenoxyethanol provoked a great reduction, while quinaldine sulphate increased IgM levels to a significant degree. These results show how the seric IgM levels can be differently affected by some immunomodulators and the important role they may play in the regulation of total circulating IgM levels in seabream. The possibility of using total serum IgM for assessing immunostimulation, disease diagnosis and stress symptoms during fish farming is discussed.     

亚麻籽和鱼油对蛋鸡蛋黄n-3多不饱和脂肪酸含量与肝脏脂肪酸代谢的影响

本试验旨在研究饲粮中添加亚麻籽和鱼油对蛋鸡蛋黄n-3多不饱和脂肪酸含量、肝脏脂肪酸组成及其合成代谢基因表达的影响。选择28周龄海兰褐壳蛋鸡96只,随机分为4组,每组24只。对照组饲喂基础饲粮,试验组分别在基础饲粮中添加10%亚麻籽、10%亚麻籽+5%鱼油和5%鱼油。饲养21 d后连续收集7 d鸡蛋,然后每组随机选取4只鸡屠宰取样。结果表明,与对照组相比:1)添加亚麻籽和鱼油均显著增加蛋黄中n-3多不饱和脂肪酸含量(P0.05),其中单独添加鱼油的蛋黄中二十二碳六烯酸(DHA)和二十碳五烯酸含量最高;2)试验组肝脏单不饱和脂肪酸比例均显著降低(P0.05),肝脏n-3多不饱和脂肪酸比例均显著增加(P0.05);3)单独添加鱼油显著降低肝脏脂肪酸延长酶1、脂肪酸延长酶2和去饱和酶(脂肪酸去饱和酶1、脂肪酸去饱和酶2和硬脂酰辅酶A去饱和酶1)基因表达水平(P0.05)。由此可见,蛋鸡饲粮中单独添加亚麻籽或鱼油可以富集蛋黄n-3多不饱和脂肪酸沉积;添加亚麻籽促进肝脏α-亚麻酸转化生成DHA过程,表现为上调脂肪酸延长酶和去饱和酶基因表达,添加鱼油显示相反结果。     

Preliminary assessment of dietary mannanoligosaccharides on growth performance and health status of gilthead seabream Sparus auratus

A feeding trial was performed to assess the potential beneficial effect of two levels of mannanoligosaccarides (MOS) on the growth performance, feed utilization, hematological parameters, and liver histopathology of gilthead seabream Sparus auratus (also known as gilthead bream). Mannanoligosaccarides were added at the rates of 2 and 4 g/kg to a fish-meal-based control diet, and each diet was given (twice daily [midmorning and midafternoon] to apparent satiation) to triplicate groups of gilthead seabream growers (mean weight = approximately 170 g) in sea cages. The trial lasted 12 weeks, and the average ambient water temperature ranged from 19.6 degrees C to 24.7 degrees C during the experimental period. At the end of the experiment, fish attained market size (350-450 g) and their health status was evaluated by blood analysis and liver histology. There were no differences in survival rates among fish fed experimental diets. However, there were significant improvements in both growth and feed utilization among fish fed diets supplemented with MOS. Hemoglobin (Hb) and hematocrit (Ht) levels and erythrocyte, leukocyte, and thrombocyte (Thr) counts were unaffected by any dietary MOS. The levels of Hb (g/dL; mean +/- SD) and Ht (%; mean +/- SD) were 11.0 +/- 2.5 and 45.6 +/- 6.7 for the control group, 11.1 +/- 1.7 and 39.3 +/- 8.0 for the 2-g/kg group, and 11.2 +/- 1.9 and 40.2 +/- 8.4 for the 4-g/kg group. The mean Thr count ranged from 47.6 to 53.8 x 10(3)/mm3. Despite the apparently higher Thr counts for fish fed diets supplemented with MOS, these differences were not significant. Moreover, no histopathological differences were observed in liver tissue cross sections between control and treatment groups. These results suggest that supplementation of diets with MOS had no significant effects on general fish health.     

Urease activity in the digestive tract of the chick and its role in the utilisation of urea as a source of non-amino nitrogen

Urease activity was found in caecal contents (about 10 mg urea metabolised/g h) and crop contents (about 0-5 mg urea metabolised/g h):there was very low activity in the contents of the colon but none in the rest of the digestive tract. 2. The urease activity of the crop contents was not bacterial in origin but the soyabean meal contained in the diet was found to have comparable activity. 3. Diets low in non-essential nitrogen and based on soyabean, fish meal or fish meal plus 0-2% jack bean urease, did not support higher growth rates when supplemented with urea. 4. The livers of chicks fed on the diet containing fish meal, urea and urease had significantly higher concentrations of free non-essential amino acids than those of chicks fed on the same diet but with urease excluded This suggested that dietary urease affects the availability of ammonia for the synthesis of non-essential amino acids but not for growth.     

Immunostimulant properties of a cell wall-modified whole Saccharomyces cerevisiae strain administered by diet to seabream (Sparus aurata L.)

The possible differences in the immunostimulant effects between whole wild Saccharomyces cerevisiae and a mutant strain (fks-1) administered in the diet to gilthead seabream (Sparus aurata L.) were studied. Fish were fed diets containing 0 (control) or 10 g whole wild yeast or fks-1 strain per kilogram feed for 2, 4 or 6 weeks. After each sampling, the innate humoral (complement, lysozyme and peroxidases) and cellular (intracellular peroxidases, phagocytosis, respiratory burst activity and cytotoxicity) responses were determined. Among the humoral responses, serum peroxidases and complement activity were significantly decreased after 6 weeks of feeding with the fks-1 strain-supplemented diet, while lysozyme activity increased after 2 and 4 weeks of feeding the fks-1 strain. Of the cellular responses studied, phagocytosis was increased to a significant degree at all the assayed times but only by the fks-1 strain-supplemented diet, while respiratory burst activity (after 4 weeks) and natural cytotoxicity (after 4 and 6 weeks) increased with either yeast strain. The intracellular peroxidase content was not affected by the dietary supplementation of either yeast strain. These results are discussed with a view to assessing the possible use of wild and/or mutant yeast strains for immunostimulant purposes in aquaculture.     

脂肪和L-肉碱对大口黑鲈饲料中蛋白质的节约作用

本试验旨在探讨脂肪和L-肉碱对大口黑鲈饲料中蛋白质的节约作用.采用3 × 2(蛋白质脂肪比×L-肉碱)完全随机设计,配制了不同蛋白质脂肪比(39.9%/7.4%、30.3%/13.9%和21.5%/19.5%)和L-肉碱水平(0和1 g/kg饲料)的6种等能饲料.选取平均初重为(3.27±0.21)g的大口黑鲈幼鱼270尾,随机分为6组(每组3个重复,每个重复15尾),随机饲喂1种饲料,试验期6周.结果表明:随着饲料中脂肪水平从7.4%升高到19.5%(蛋白质水平从39.9%下降到21.5%),鲈鱼的增重率从685%显著降低到176%(P<0.05),饲料效率从1.15增加到2.33(P<0.05),且投喂蛋白质脂肪比为21.5%/19.5%饲料的鲈鱼的肥满度显著低于投喂蛋白质脂肪比为39.9%/7.4%和30.3%/13.9%饲料的鲈鱼(P<0.05).投喂蛋白质脂肪比为21.5%/19.5%饲料的鲈鱼体水分含量显著低于投喂蛋白质脂肪比为39.9%/7.4%的饲料(P<0.05),且随着饲料中脂肪水平从7.4%升高到19.5%(蛋白质水平从39.9%下降到21.5%).全鱼脂肪含量从5.6%显著升高到11.5%(P<0.05),全鱼粗蛋白质含量从15.6%显著下降到10.4%(P<0.05).鱼体肝脏和肌肉中脂肪含量以及肝体指数在投喂蛋白质脂肪比为21.5%/19.5%饲料时达到最高值.此外,随着饲料中脂肪水平从7.4%升高到19.5%(蛋白质水平从39.9%下降到21.5%),淋巴细胞百分比由38.30%升高到48.41%(P<0.05),粒细胞百分比由51.75%下降到42.14%(P<0.05).由此得出,以节约蛋白质为目的的过量添加脂肪会导致鱼体生长速度降低,甚至引起脂肪肝的发生和机体免疫系统的应激反应.此外,饲料中添加1 g/kg的L-肉碱并不能提高大口黑鲈的生长性能,但蛋白质脂肪比和L-肉碱对淋巴细胞百分比和粒细胞百分比存在互作作用,并在饲喂添加1 g/kg L-肉碱的蛋白质脂肪比为21.5%/19.5%的饲料时达到峰值.     

RADIOGRAPHIC ASSESSMENT OF GASTRIC EMPTYING AND GASTROINTESTINAL TRANSIT TIME IN HYBRID TILAPIA (OREOCHROMIS NILOTICUS×O. MOSSAMBICUS)

Hybrid tilapias (Oreochromis niloticus x O. mossambicus) were studied to determine gastric emptying and gastrointestinal transit time. The fish were divided into two groups. All fish were fasted for 12 h. The first experiment consisted of 11 fish fed with commercial food pellets and then administration of barium sulfate directly into the stomach using a blunt-end needle. Fish were then radiographed at different time intervals. The second experiment consisted of eight fish, which were given only barium sulfate after 12 h of fasting. In the first experiment, the stomach emptied completely, ranging from 4 to 15h postcontrast medium administration, whereas the gastrointestinal transit time ranged between 10 and 26 h. As for the second experiment, the contrast medium was still retained in the stomach in 50% of the fish after 24 h. The study did not proceed beyond 24 h as fish were considered stressed after this period of time. Thus, no data for the gastrointestinal transit time was obtained.     

The effects of levamisole on oxidative stress induced by copper intoxication in broilers

Abstract

AIM: To determine the effects of Cu and levamisole on concentrations of Cu and Fe in plasma and liver, and the effects of levamisole on lipid peroxidation induced by Cu intoxication in broiler chickens.

METHODS: In a 2×4 factorial study, 80 one-day-old Ross PM3 broiler chicks were fed diets for 21 days containing either 8 mg/kg Cu (Low Cu) or 250 mg/kg Cu (High Cu) and were treated with 0 (L0), 4 (L4), 8 (L8) or 16 (L16) mg/kg bodyweight levamisole per day from Day 7 of the study, on three consecutive days in their drinking water. This treatment was repeated three times, at 3-day intervals. On Day 21, blood samples were collected from each bird for analysis of concentrations of Cu, Fe and malondialdehyde, and activities of aspartate aminotransferase (AST), alanine aminotransferase (ALT), superoxide dismutase, catalase and glutathione peroxidase (GSH-Px). The birds were killed and liver samples collected for analysis of Cu and Fe.

RESULTS: Mean concentrations of Cu and Fe in plasma, and Cu in liver, were increased overall in the High Cu groups compared with the Low Cu groups (p<0.001). Compared with the L0 treatment group on the High Cu diet, treatments L4, L8 and L16 decreased concentrations of Cu in plasma, and L8 and L16 increased concentration of Cu in liver (p<0.05). Mean activities of AST and ALT were increased in untreated birds (L0) fed the High compared with Low Cu diets (p<0.01). In birds receiving the High Cu diet, treatments L4 and L8 decreased activities of AST, and L4 and L16 decreased activity of ALT, compared with L0 (p<0.05). The High Cu diet induced an oxidative stress characterised by increased mean concentrations of malondialdehyde and decreased activities of superoxide dismutase, catalase and GSH-Px (p<0.001). Concentration of malondialdehyde, and activities of superoxide dismutase and catalase were not changed following levamisole treatment in birds on the High Cu diet, and activity of GSH-Px was decreased by the L4 and L8 treatments compared with the L0 group.

CONCLUSIONS AND CLINICAL RELEVANCE: The results of the study suggest that treatment with levamisole might alleviate the harmful effects of Cu on the liver, as demonstrated by decreased activities of AST and ALT induced by a diet containing 250 mg/kg Cu.     

豆油部分或全部替代饲料中鱼油对中华条颈龟肠道形态及菌群结构的影响

本试验通过组织学染色及16S rRNA V3~V4区测序研究豆油部分或全部替代饲料中鱼油对中华条颈龟(Mauremys sinensis)肠道形态及菌群结构的影响。选取中华条颈龟雌龟[4龄,平均体重(1 557±307)g]24只,随机分为4组,每组6只。Ⅰ组(对照组)饲喂含1%鱼油的配合饲料(全鱼油饲料,豆油与鱼油的比例为0∶3),3个试验组分别饲喂用豆油替代全鱼油饲料中33%(Ⅱ组,豆油与鱼油的比例为1∶2)、67%(Ⅲ组,豆油与鱼油的比例为2∶1)和100%(Ⅳ组,豆油与鱼油的比例为3∶0)鱼油的饲料。每周喂食2次,试验期为10个月。结果表明:1)Ⅰ和Ⅲ组十二指肠绒毛长/隐窝深度(VH/CD)显著高于Ⅱ和Ⅳ组(P0.05)。2)根据序列相似性97%水平划分,Ⅰ、Ⅱ、Ⅲ和Ⅳ组操作分类单元(OTU)总数分别为396、321、347和331个,特有OTU个数分别为43、3、4和5个,分别被鉴定出139、117、128、120个属。十二肠道优势菌门主要包含拟杆菌门(Bacteroidetes)、厚壁杆菌门(Firmicutes)、梭杆菌门(Fusobacteria)和变形菌门(Proteobacteria)4个门。Ⅱ、Ⅲ和Ⅳ组梭杆菌门和变形菌门所占比例增加,拟杆菌门和厚壁菌门所占比例下降,Ⅲ组厚壁杆菌门和拟杆菌门所占比例与Ⅰ组差距最小。细菌Ace指数和香农指数表现为Ⅰ组最高,其次是Ⅲ和Ⅳ组,Ⅱ组最小;细菌辛普森指数表现为Ⅱ组最大,其次是Ⅲ和Ⅳ组,Ⅰ组最小。由此得出,饲喂用豆油替代67%鱼油的饲料的中华条颈龟的肠道细胞发育成熟度以及菌群结构与饲喂全鱼油饲料的中华条颈龟相近。     

Korean mistletoe enriched diet enhances innate immune response in kelp grouper, Epinephelus bruneus against Philasterides dicentrarchi

The present study investigated the immunostimulatory effect of Korean mistletoe Viscum album extract (KM-E) on innate immune response in kelp grouper Epinephelus bruneus against Philasterides dicentrarchi. Kelp grouper were divided into four groups of 25 each and fed with 0 (control), 0.5, 1.0, and 2.0% enriched diets with Korean mistletoe extract (KM-E). After feeding for 30 days, the fish were injected intraperitoneally (i.p.) with 100 μl of P. dicentrarchi (4.2 × 10(7)ciliates/ml) to study the immune responses at weeks 1, 2, and 4. The respiratory burst activity did not significantly enhance when fed with 0.5% and 1.0% supplementation diets on week 1 when compared to control diet. On weeks 2 and 4, the respiratory burst activity significantly increased with 1.0% and 2.0% diets. The phagocytic activity significantly enhanced with 1.0% and 2.0% diets, but not with 0.5% diet at any time. When fed with 1.0% KM-E-diet the lysozyme activity did not significantly vary at any week whereas with 1.0% and 2.0% diets it was significantly enhanced. The total protein level significantly increased with 1.0% and 2.0% KM-E-diets from weeks 1 to 4 as compared to control. The present study suggests that 1.0% or 2.0% KM-E-supplementation diet positively enhances the innate immune response in E. bruneus against P. dicentrarchi infection.     

Preliminary Assessment of Dietary Mannanoligosaccharides on Growth Performance and Health Status of Gilthead Seabream Sparus auratus

Abstract

A feeding trial was performed to assess the potential beneficial effect of two levels of mannanoligosaccarides (MOS) on the growth performance, feed utilization, hematological parameters, and liver histopathology of gilthead seabream Sparus auratus (also known as gilthead bream). Mannanoligosaccarides were added at the rates of 2 and 4 g/kg to a fish-meal-based control diet, and each diet was given (twice daily [midmorning and midafternoon] to apparent satiation) to triplicate groups of gilthead seabream growers (mean weight = approximately 170 g) in sea cages. The trial lasted 12 weeks, and the average ambient water temperature ranged from 19.6°C to 24.7°C during the experimental period. At the end of the experiment, fish attained market size (350–450 g) and their health status was evaluated by blood analysis and liver histology. There were no differences in survival rates among fish fed experimental diets. However, there were significant improvements in both growth and feed utilization among fish fed diets supplemented with MOS. Hemoglobin (Hb) and hematocrit (Ht) levels and erythrocyte, leukocyte, and thrombocyte (Thr) counts were unaffected by any dietary MOS. The levels of Hb (g/dL; mean ± SD) and Ht (%; mean ± SD) were 11.0 ± 2.5 and 45.6 ± 6.7 for the control group, 11.1 ± 1.7 and 39.3 ± 8.0 for the 2-g/kg group, and 11.2 ± 1.9 and 40.2 ± 8.4 for the 4-g/kg group. The mean Thr count ranged from 47.6 to 53.8 × 10³/mm³. Despite the apparently higher Thr counts for fish fed diets supplemented with MOS, these differences were not significant. Moreover, no histopathological differences were observed in liver tissue cross sections between control and treatment groups. These results suggest that supplementation of diets with MOS had no significant effects on general fish health.

Received February 20, 2011; accepted September 12, 2011     

Effect of Low Dietary Magnesium on Immune Response and Osmoregulation of Atlantic Salmon

Abstract

The influences of dietary magnesium on immune response and on osmoregulation in parr of Atlantic salmon Salmo salar were determined. Groups of fish were fed a casein–gelatin diet unsupplemented (containing about 200 mg Mg/kg) or supplemented with either 300 or 500 mg Mg/kg dry diet (as MgSO₄) for 12 weeks before vaccination to produce fish with different Mg levels, and the feeding regime was continued throughout the study. No differences were observed between the treatment groups in serum-specific antibody levels every second week for 8 weeks after vaccination against Vibrio anguillarum serotypes O1 and O2. Both lysozyme levels and spontaneous hemolytic activities in serum were elevated in vaccinated fish compared with unvaccinated fish. Neither lysozyme activity, complement hemolytic activity, total protein in serum nor blood hemoglobin were affected by dietary Mg. The spontaneous hemolytic activity in serum was lower in fish fed the unsupplemented diet and highest in fish fed the diet supplemented with 500 mg Mg/kg. After 28 weeks on the diets supplemented with graded levels of Mg, a salinity tolerance test (32.5 g/L, 24 h) was performed. High mortality and elevated serum chloride concentrations in all groups after 24 h reflected a general salinity intolerance, but the highest serum chloride level was observed in fish fed the unsupplemented diet. This indicates that low dietary Mg affects the osmoregulation of Atlantic salmon.     

Effects of carbohydrate sources on growth,body composition and tissue lipid deposition of blackspot seabream,Pagellus bogaraveo (Brunnich)

Rearing blackspot seabream has been associated with low growth rates and excessive lipid accumulation, resulting in a reduction of the edible yield. The effect of extruded diets containing different carbohydrate sources (wheat vs. wheat bran) was evaluated on 100 g blackspot seabream growth performance, feed utilization and fat deposition, taking into consideration the optimal dietary protein and lipid level described for smaller‐sized fish. A fish meal‐based diet was also tested as a control to assure maximal growth rates were achieved. The experiment was held in sea cages at environmental conditions. Duplicate groups of fish were distributed among six cages with a stocking density of 1.3 kg/m³ and hand‐fed each diet for 7 months. At the end of the experiment, fish in all groups doubled their body weight attaining 190–230 g. Specific growth rate (0.3–04), feed conversion ratio (1.3–1.6) and protein gain (0.5–0.6 g/kg/day) were similar among treatments. The Hepatosomatic Index, the Viscerosomatic Index and final whole body composition did not vary significantly among dietary treatments; nevertheless, the inclusion of wheat bran induced a significant increase of liver lipid content and the highest mesenteric fat index. All diets were effective in reducing whole body and mesenteric fat compared with initial values.     

Dietary conjugated linoleic acids alleviate early inflammatory response caused by lipopolysaccharide injection in male broiler chicks

An experiment was undertaken to determine if dietary conjugated linoleic acid (CLA) influences the early stage of the inflammatory response caused by a single injection of Salmonella enteritidisi lipopolysaccharide (LPS) in male broiler chicks. Chicks (7 days old) were fed either 0 or 10 g CLA/kg in their diet for 21 days. At 28 days old, birds were injected intraperitoneally with 1.5 mg LPS/kg body weight after 12 h fasting. Changes in feed intake, rectal temperature and plasma α‐1 acid glycoprotein and ceruloplasmin concentrations were measured during 24 h after LPS injection. Chicks fed the CLA diet were fed more feed for 24 h, had a lower rectal temperature at 9 and 24 h and a lower plasma α‐1 acid glycoprotein concentration at 24 h after LPS injection than chicks fed the basal diet. Plasma ceruloplasmin concentration tended to be lower in chicks fed the CLA diet than in chicks fed the basal diet. The results suggest that dietary CLA alleviate undesirable early inflammatory response due to LPS injection in male broiler chicks.     

Influence of dietary conjugated linoleic acid isomers on early inflammatory responses in male broiler chickens

1. The influence of dietary conjugated linoleic acid isomer (CLA, 0 and 10 g/kg) on the metabolic and physiological responses to immune stimulation induced by a single injection of Salmonella enteritidis lipopolysaccharide (LPS) or repeated injections of LPS and Sephadex G-50 was determined in male broiler chicks. 2. In experiment 1, 10-d-old chicks were fed on experimental diets for 14 d and half of the birds fed on each diet were injected intraperitoneally with LPS (1.5 mg/kg body weight). In experiment 2,7-d-old chicks were fed on experimental diets for 18 d. Immune stimulation was started at 19 d old and continued for 5 d. Half of the birds fed on each diet were injected intraperitoneally with 0.25 mg/kg body weight of LPS at 19, 21 and 23 d of age, and with 250 mg/kg body weight of Sephadex at 20 and 22 d of age to stimulate the immune system. 3. In experiment 1, giving CLA prevented an increase in blood heterophil to lymphocyte ratio 7 h after a single injection of LPS, and increases in plasma ceruloplasmin and alpha 1 acid glycoprotein (AGP) 24 h after the injection, but not 7 h after the injection. CLA also prevented a decrease in food intake for 24 h after LPS injection. 4. In experiment 2, the CLA diet partially prevented reductions in body weight gain and weight gain to feed intake ratio caused by repeated injections of LPS and Sephadex. Feeding CLA prevented increases in plasma ceruloplasmin and AGP at 24 d of age caused by repeated injections of LPS and Sephadex, but not at 20 d of age. 5. These results suggest that feeding CLA alleviates some undesirable metabolic and physiological changes induced by immunological stimulation in male broiler chicks.     

Effect of dietary supplementation of fish oil for lactating sows and weaned piglets on piglet Th polarization

The present study was designed to investigate the effect of dietary fish oil supplementation on piglet T helper cells (Th) polarization in relation to its impact on piglet serum interferon γ (IFN-γ) and interleukin 10 (IL-10) concentrations and splenic expression of Th1/Th2 characteristic genes. The diets of 18 gestating sows were supplemented with 7% lard (C) (n = 10) or 7% fish oil (T) (n = 8) from 10 d before parturition to weaning. At weaning, a split plot experiment was designed, 56 piglets, 28 each from sows fed with fish oil diet or lard diet, were divided into four groups of 7 replicates (one female and one castrated male per replicate) based on both sow diet during lactation and post-weaning piglet diet (C had 7% lard and T had 7% fish oil): CC, CT, TC, TT, and were fed the 7% fish oil or lard diet from day 35 to day 70. Serum concentrations of IFN-γ and IL-10, and Th1/Th2 related genes expression levels in spleen were measured and analyzed. The results showed that piglets fed with fish oil diet during post-weaning tended to have higher serum IFN-γ/IL-10 ratio (P = 0.09) than lard diet fed piglets. Lactation fish oil feeding increased splenic IL-12b, IL-12 receptor β2 (IL-12Rβ2), IL-2 and IFN-γ genes expression (P < 0.05 or P < 0.01) and post-weaning fish oil feeding increased splenic IL-12b (P = 0.06), IL-2 (P < 0.01) and IFN-γ (P = 0.08) mRNA expression than that in lard diet fed piglets at the end of this experiment. On the other hand, IL-4 gene expression (P = 0.01) in spleen was lower in weaned piglet from fish oil diet fed sows than that from lard diet fed sows. However, post-weaning piglets fed fish oil diet had higher splenic IL-4 (P = 0.06), IL-6 (P < 0.01) and IL-10 (P = 0.05) mRNA abundances than that fed with lard diet. These results indicated that dietary fish oil during lactation could increase Th1 polarization and accelerate immune maturation; while 7% fish oil in weaned piglets' diet was likely to increase Th2 cytokines expression.     

低磷低鱼粉饲料中添加植酸酶和蛋白酶对草鱼生长性能和消化生理的影响

本试验旨在研究低磷低鱼粉饲料中添加植酸酶和蛋白酶对草鱼生长性能、消化酶活性、营养物质表观消化率和免疫力的影响。试验选取平均体重为9.66 g的健康草鱼630尾,随机分为7个组,每组3个重复,每个重复30尾鱼。7组草鱼饲喂如下试验饲料:正常磷(磷酸二氢钙添加量2.0%)正常鱼粉(鱼粉添加量3.0%)饲料(对照)、低磷(磷酸二氢钙添加量1.3%)正常鱼粉饲料、低磷正常鱼粉并添加0.03%植酸酶饲料、正常磷低鱼粉(鱼粉添加量1.5%)饲料、正常磷低鱼粉并添加0.05%蛋白酶饲料、低磷和低鱼粉饲料、低磷低鱼粉并添加0.03%植酸酶和0.05%蛋白酶饲料。饲养试验持续56 d。结果显示:与饲喂正常磷正常鱼粉饲料草鱼相比,饲喂低磷低鱼粉饲料草鱼的增重率、特定生长率、营养物质(干物质、蛋白质、钙和磷)表观消化率、肠道消化酶(胰蛋白酶、糜蛋白酶和淀粉酶)活性、血清溶菌酶活性均显著降低(P<0.05),饲料系数和血清丙二醛含量显著升高(P<0.05)。在低磷正常鱼粉饲料、正常磷低鱼粉饲料、低磷低鱼粉饲料中分别添加植酸酶、蛋白酶、植酸酶与蛋白酶后,草鱼的上述指标均得到显著改善(P<0.05)。以上结果表明,在低磷低鱼粉饲料中添加植酸酶和蛋白酶能够提高草鱼的营养物质表观消化率、肠道消化酶活性和免疫力,从而改善其生长性能。