Dietary Supplementation with Allspice Pimenta dioica Reduces the Occurrence of Streptococcal Disease during First Feeding of Mozambique Tilapia Fry

Abstract

Allspice Pimenta dioica as a feed additive was studied for its effects on growth performance and disease resistance in Mozambique Tilapia Oreochromis mossambicus. Five isonitrogenous (36% crude protein) and isocaloric (18.5 kJ/g) diets were formulated to contain 0 (control), 5, 10, 15, or 20 g of allspice/kg of fish feed. In a 50-d feeding trial, 15 plastic tanks (21 L) were stocked with 35 fish fry (0.012 g) each. After the feeding trial, fish were exposed to Streptococcus iniae and mortalities were recorded. The second-order polynomial regression indicated that the dietary allspice level of 10 g/kg provided the best growth performance and feed utilization. The greatest survival after pathogen challenge was also obtained from the diet supplemented with allspice at 10 g/kg. Therefore, allspice acts as a growth promoter to improve feed utilization and weight gain in Mozambique Tilapia fry and acts an antimicrobial agent to enhance disease resistance during first feeding of fry. These results suggest that allspice can be used as an alternative to antibiotics in controlling streptococcal disease in tilapia culture.

Received October 19, 2012; accepted January 20, 2014     

Hatchery Efficacy Trials with Chloramine-T for Control of Bacterial Gill Disease

Abstract

Three hatchery trials were carried out to determine the efficacy of chloramine-T for the control of bacterial gill disease in rainbow trout Oncorhynchus mykiss, ranging in weight from 2.5 to 54 g. In each trial, we used a single flow-through treatment of 8.5 mg chloramine-T/L. The single treatment provided effective control in all three trials; however, results were best when treatment was begun in the early stages of an outbreak. A second or third treatment may be required if an outbreak is in an advanced stage or if fish are under stress.     

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     

Effects of dietary β‐(1,3)(1,6)‐D‐glucan supplementation on growth performance,intestinal morphology and haemato‐immunological profile of mirror carp (Cyprinus carpio L.)

In recent years, aquaculture research has focused on probiotics, prebiotics, and β‐glucans, in order to improve health status and growth performance. Information regarding the effects of β‐glucan on growth performance and intestinal immunity of mirror carp (Cyprinus carpio L.) is scarce. An experiment was therefore conducted to investigate the effects of a yeast β‐glucan preparation (MacroGard^®) on growth performance, intestinal morphology and haemato‐immunological indices of mirror carp. Carp (initial weight 11.1 ± 0.0 g) were fed highly purified diets supplemented with 0% (control), 0.1%, 1% or 2% MacroGard^® for 8 weeks. Fish fed diets containing 1% and 2% MacroGard^® showed significant improvements in weight gain, specific growth rate and feed conversion ratio compared to fish fed both the control and the 0.1% MacroGard^® containing diet. Histological appraisal of the intestine showed a significantly higher infiltration of leucocytes into the epithelial layer of fish fed diets supplemented with 1% and 2% MacroGard^® in the anterior intestine compared to fish fed the control and 0.1% MacroGard^® diet. This effect was not observed in the posterior intestine. There were no significant differences in the intestinal absorptive surface area and number of goblet cells in either intestinal region. At the end of the experiment, the haematological status of the fish was examined. Compared to control fed fish, the haematocrit value was significantly elevated in fish fed the 2% MacroGard^® diet. Furthermore, the blood monocyte fraction was significantly higher in fish fed the 1% and 2% MacroGard^® diets. No significant changes were observed in the other blood parameters assessed. The present study shows that high dietary β‐glucan inclusion increases growth performance without detrimental effects on the health indicators assessed. Increased intraepithelial leucocytes in the anterior intestine may indicate a localized immune response; no detrimental effects on intestinal morphology were observed.     

A field efficacy evaluation of emamectin benzoate for the control of sea lice on Atlantic salmon

This study evaluated the efficacy of emamectin benzoate, 0.2% aquaculture premix, against sea lice on Atlantic salmon in eastern Canada. Salmon pens received either emamectin benzoate, orally, in feed at 50 micrograms/kg body weight/day for 7 consecutive days, or the same diet with no added medication. The site veterinarian had the option of administering a bath treatment with azamethiphos to any pen in the trial. The mean number of lice per fish was lower (P < 0.05) in the experimental group when measured 1, 3, 4, and 6 weeks after the start of medication. Treatment efficacy was 70%, 88%, 95%, and 61%, respectively. Three azamethiphos bath treatments were applied to each control pen during the trial, while the treatment pens received no bath treatment. No gravid female parasites were observed on any fish in the treatment group, while these life stages were observed on fish in the control group. Orally administered emamectin benzoate was palatable and highly effective for control of sea lice on salmon.     

Effect of Common Aquaculture Chemicals against Edwardsiella ictaluri and E. tarda

Abstract

Edwardsiellosis is an important bacterial infection of freshwater and marine fishes. Edwardsiella ictaluri causes enteric septicemia of catfish, and E. tarda causes emphysematous putrefactive disease of catfish and fish gangrene in various species; these diseases have considerable economic effects on the aquaculture industry. In addition, E. tarda is an important zoonotic pathogen. Thus, the reduction or elimination of these pathogens from an aquarium or aquaculture facility is imperative. This study examined a variety of commercially available chemicals for their ability to reduce or eliminate E. ictaluri and E. tarda from the aquatic environment. The various concentrations of chemicals were tested in vitro in microcentrifuge tubes with a known concentration of bacteria at room temperature. In this study, ethyl alcohol (30, 50, or 70%), benzyl-4-chlorophenol/phenylphenol (1%), sodium hypochlorite (50, 100, 200, or 50,000 mg/L), n-alkyl dimethyl benzyl ammonium chloride (1:256), povidone iodine (50 or 100 mg/L), glutaraldehyde (2%), and potassium peroxymonosulfate/sodium chloride (1%) were effective disinfectants, as each reduced or eliminated the number of detectable organisms within 1 min of contact time. However, neither Chloramine-T (15 mg/L) nor formalin (250 mg/L) substantially reduced bacterial counts even after 60 min of contact time.     

不同水产复合酶对芙蓉鲫的应用效果研究

试验芙蓉鲫;500尾随机分成4个组,每组5个重复．每个重复放养25尾鱼。对照组为不添加复合酶制剂的基础日粮,试验组在基础日粮下添加不同公,--j水产复合酶微丸,添加量为200g／t,养殖时间为8周。结果表明：添加水产复合酶的生长性能、对肝脏蛋白酶和淀粉酶都比对照组的高。添加了溢多利公司水产复合酶试验组的终末尾均重和增重率比对照组提高5．12％、12．09％,饵料系数降低了7．14％且差异显著（P〈0．05）,肥满度提高7．55％,差异不显著（P〉0．05）;溢多利水产复合酶对淀粉酶活性提高,分别较公司1复合酶、对照组、公司2的复合酶三组提高1．29％、3．49％、4．73％;蛋白酶的活性提高6．46％、1．77％、0．44％。由此可见,添加200g／t的溢多利水产复合酶对芙蓉鲫的生长性能和内源酶活性提高的效果是最好的。     

Influence of birth weight and nutrient supply before and after weaning on the performance of rabbit does to age of the first mating

The objective of the study was to determine the effect of birth weight and the influence of nutrient supply during nursing and after weaning on the performance of suckling and growing rabbits (n = 182). The experiment was set-up using a 3 × 2 × 2 factorial arrangement. Newborn female rabbits were divided on the basis of their birth weight in 3 classes: low /L/ = 35–45 g, medium /M/ = 53–58 g and high /H/ = 65–70 g. Half of the litters were nursed by one (O) doe and the other half by two does (T). Kits were weaned at 3 weeks of age. From the age of 4 weeks half of the rabbits were fed ad libitum (AL), while the other half were reared on a restricted feeding regime (R) corresponding to 80–85% of the ad libitum feed intake level.Birth weight had a significant effect on the body weight up to the end of the experiment (18 weeks of age). H kits attained higher body weight at all ages (3772 g at 18 weeks of age compared to 3565 g and 3373 g for L and M rabbits, respectively). Significant differences were found in feed intake between 3 and 15 weeks of age, in feed conversion between 9 and 12 weeks of age and in weight gain between 3 and 4 and 12 and 15 weeks of age, in the majority of cases in favour of the H rabbits.Nursing by one or two does exerted the most pronounced effect on the body weight. T kits had significantly higher body weight than O kits up to 15 weeks of age (3306 vs. 3108 g). Differences in feed intake, feed conversion and body weight were only periodically demonstrable between the groups O and T.The feeding regime exerted a significant influence on the feed intake, weight gain and body weight of kits. Significant differences in the feed conversion were found, however, only between 15 and 18 weeks of age. Although AL rabbits achieved better feed conversion at all ages except the period between 9 and 12 weeks of age.It seems that the three factors (birth weight, number of nursing does and feeding regime), especially the feed restriction, could influence the production of does.     

多不饱和脂肪酸对鱼饲料转化率的影响及其机理

由于过分的海洋捕捞以及对海水鱼消费的增加,导致海水鱼油供不应求,研究使用鱼油替代品发展水产养殖业势在必行。植物油供应稳定,价廉物美,但是它富含多不饱和脂肪酸(PUFAs),却缺乏高度不饱和脂肪酸(HUFAs),尤其缺乏n-3HUFAs。文章结合本研究所多年来对HUFAs的研究成果,重点综述PUFAs特别是n-3HUFAs对鱼饲料转化率的影响及其机理,并探索植物油替代鱼油存在的问题及解决方法,以促进有效利用PUFAs和用植物油替代鱼油养殖海水鱼,发展可持续的海水养殖业。     

Journal of Aquatic Animal Health: Guide for Authors 2014

Abstract

Brook trout Salvelinus fontinalis were treated with single 60-min static baths of 250 mg formalin/L, 3% NaCl, and 15 mg Chloramine-T/L to evaluate the efficacy of these compounds against external infections of Aeromonas salmonicida. Prevalence of A. salmonicida was significantly lower in brook trout treated with Chloramine-T than among those treated with formalin or salt. Further laboratory tests substantiated the therapeutic value of a single treatment of ChloramineT (15 mg/L) against A. salmonicida. In two experiments, viable counts of A. salmonicida in mucus did not vary among replicate groups of treated brook trout, but the counts for treated fish were significantly (P < 0.05) lower than those for untreated controls. In vitro tube dilution assays indicated that mean minimum inhibitory concentrations of Chloramine-T for 10 isolates of A. salmonicida were 9.0 mg/L for 1 h and 2.25 mg/L, for 24 h. In field trials at the White River National Fish Hatchery (Bethel, Vermont), the pathogen was detected principally as an external infection of juvenile Atlantic salmon Salmo solar maintained in two culture ponds. In one pond, the bacterium accounted for 100% of the total distribution of tnicroflora isolated from mucus. Seven days after treatment with Chloramine-T, A. sahnonicida accounted for 11% of the total bacterial counts identified from these fish. In the second pond, A. salmonicida composed 3% of the counts of bacteria isolated from the mucus of fish before treatment but was not isolated after treatment.     

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.     

The Effects of Replacing Rhodes Grass (Chloris gayana) Hay with Ghaf (Prosopis cineraria) Pods on the Performance of Omani Native Sheep

A feeding trial using various levels of dry pods of ghaf (Prosopis cineraria) was carried out with 28 Omani native male sheep. Individual feed intake and body weight were determined for 50 days to allow assessment of the effects of the feeds on growth, feed intake, feed conversion and carcase measurements. The ripened ghaf pods contained 91% dry matter (DM), 13.5% crude protein (CP), 14.3% crude fibre (CF), 1.3% ether extract (EE) and 5.2% ash (on DM basis). Four levels of ghaf (0, 15%, 30% and 45%) were used with corresponding decreasing proportions of Rhodes grass (RGH) hay. Animals fed rations containing RGH as the sole source of roughage and no ghaf grew faster (135 g/day) and had better feed conversion than those fed various levels of ghaf. Sheep fed 15% ghaf gained reasonably well (90 g/day) and had carcase attributes similar to those fed no ghaf. Sheep fed 30% ghaf still gained weight but those fed 45% ghaf lost weight. Negative effects on growth appeared to occur after 6 weeks of feeding ghaf.     

Effect of dietary ascorbic acid supplementation level on productivity,mortality, and carcass characteristics of Venda chickens

Two experiments were carried out to determine the effect of dietary ascorbic acid supplementation levels on productivity, carcass characteristics, and mortality of indigenous Venda chickens. The first experiment determined the effect of dietary ascorbic acid supplementation levels on productivity and mortality rate of 175 unsexed Venda chickens between 1 and 6 weeks old. The second experiment determined the effect of dietary ascorbic acid supplementation levels on productivity, carcass characteristics, and mortality rate of 140 female Venda chickens between 8 and 13 weeks old. A completely randomized design was used in both experiments. Supplementation of grower diets with ascorbic acid ranged from 0 to 2,000 mg per kg DM feed in both experiments. Levels of ascorbic acid supplementation for optimum feed intake, feed conversion ratio, growth rate, live weight, and breast meat yield were determined using a quadratic equation. The optimal dietary ascorbic acid supplementation levels for feed conversion ratio, growth rate, and live weight of Venda chickens during the starter phase were 1,050, 1,301, and 1,500 mg/kg DM feed, while, at the grower phase, the optimal supplementation levels for feed conversion ratio, growth rate, live weight, and breast meat yield were 1,000, 1,250, 1,482, and 769 mg/kg DM feed, respectively. Results indicate that different levels of ascorbic acid supplementation optimized feed conversion ratio, growth rate, and live weight of Venda chickens at each growth phase. However, levels of ascorbic acid supplementation for optimum feed conversion ratio, growth rate, and live weight were higher than that for breast meat yield. These findings have implications on ration formulation for Venda chickens.     

Présence de la maladie bactérienne du rein chez les salmonidés au Québec

Presence of the bacterial kidney disease in salmonid fish in Quebec During the summers of 1979 and 1980, wild and hatchery fish were analysed for the presence of the bacterial kidney disease (BKD) agent in salmonid fish in Quebec by the indirect immunofluorescence technique. The causative agent of BKD was detected in all hatcheries tested. Ten to 25% of the fish were positive. The presence of this agent was independent of age and species. We were unable to detect the BKD in fish from the rivers in the northern part of Quebec (over the 50th parallel).     

Effects of exogenous cortisol on the GH/IGF-I/IGFBP network in channel catfish

Glucocorticoids are known to hinder somatic growth in a number of vertebrate species. In order to better understand the mechanisms through which they may act in channel catfish, we examined the effects of feeding cortisol on the growth hormone (GH)/insulin-like growth factor-I (IGF-I)/IGF-binding protein (IGFBP) network. Fish (30.6 ± 3.0 g) were fed once daily for 4 weeks and treatments included: (1) High-cortisol (dietary cortisol provided at 400 mg/kg feed), (2) Low-cortisol (dietary cortisol provided at 200 mg/kg feed), and (3) Control (commercial catfish feed). Fish fed diets with cortisol weighed approximately 50% less than Controls. Feed intake was reduced by approximately 30% in both treatments of cortisol fed fish compared to Controls. A 20-kDa IGFBP was observed in plasma from High- and Low-treated fish while it was not detected in Control fish plasma. High-cortisol treatment increased pituitary GH mRNA expression approximately 10-fold while liver IGF-I mRNA expression was not different between cortisol-treated fish and Controls. Cortisol treatments decreased plasma levels of IGF-I. These data indicate that feeding cortisol for 4 weeks reduces weight gain, feed intake, and plasma levels of IGF-I and induces a 20-kDa IGFBP. One mechanism through which cortisol may impede growth of catfish is through an increase in a low molecular weight IGFBP which may lead to inhibitory effects on the action of IGF-I.     

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.     

4种诱食剂对杂交鳢生长和血清生化指标的影响

为评价鱼溶浆、酵母膏、二甲基-β-丙酸噻亭(DMPT)和复合诱食剂对杂交鳢的诱食效果,配制了1种基础饲料(对照组),以及在基础饲料中分别添加2.0%鱼溶浆、2.0%酵母膏、0.1%DM PT和0.1%复合诱食剂的4种试验饲料,饲喂初始均重(17.30±0.03)g的杂交鳢8周。5种饲料等氮等能(粗蛋白质42%,总能18 MJ/kg)。结果显示:添加诱食剂组杂交鳢的终末均重(FABW)、增重率(WGR)和特定生长率(SGR)显著高于对照组(P0.05),而酵母膏组和复合诱食剂组杂交鳢的FABW、WGR、SGR和摄食率(FI)显著高于鱼溶浆组和DMPT组(P0.05)。各组蛋白质效率(PER)和饲料系数(FCR)无显著差异(P0.05)。同对照组相比,鱼溶浆组、酵母膏组和复合诱食剂组杂交鳢的肝体比(HSI)显著降低(P0.05),脾体比(SSI)显著升高(P0.05)。而复合诱食剂组杂交鳢的脏体比(VSI)显著低于其他各组(P0.05)。与对照组相比,鱼溶浆组、酵母膏组和复合诱食剂组杂交鳢的血清胆固醇(CHO)、丙二醛(MDA)含量显著降低(P0.05),血清总蛋白(TP)含量及超氧化物歧化酶(SOD)、过氧化氢酶(CAT)活性显著升高(P0.05)。各组血清甘油三酯(TG)、球蛋白(GLOB)含量及碱性磷酸酶(ALP)活性无显著差异(P0.05)。由此可见,饲料中添加诱食剂可以提高杂交鳢的摄食量,降低血脂水平,同时提高鱼体免疫力和抗氧化能力,进而促进其生长,以酵母膏和复合诱食剂的效果较佳。     

Dietary replacement of fish meal by defatted and fermented soybean meals with taurine supplementation for pompano fish: effects on growth performance,nutrient digestibility,and biological parameters in a long-term feeding period

A 16-wk growth trial was conducted to examine the effects of dietary replacement of fish meal by defatted soybean meal (SBM) and fermented soybean meal (FSBM) with taurine supplementation on growth performance, nutrient apparent digestibility coefficient (ADC) and biological parameters of pompano fish. The FSBM was produced by fermenting SBM with Lactobacillus spp. Seven isonitrogenous and isoenergetic diets were formulated to replace 35% or 50% of fish meal by SBM or FSBM with taurine supplementation. The diets are denoted as follows: FM, SBM35, SBM35T, FSBM35T, SBM50, SBM50T, and FSBM50T. The FM (the basal diet) contained fish meal as a main source of dietary protein. Taurine was supplemented to SBM35T, FSBM35T, SBM50T, and FSBM50T at the level of 15 g/kg diet. Pompano juveniles with an initial body weight (BW) of 80 g reared in floating net cages were fed the experimental diets twice daily for 16 wk. Results showed that the final BW, weight gain, and feed conversion ratio of fish fed SBM35 and SBM50 were significantly lower than those of fish fed FM (P < 0.05), indicating that the replacement of fish meal by SBM at the rate of 35% in the diet is excessive for pompano. Supplementation of taurine to the SBM-included diets significantly increased growth performance and feed utilization (P < 0.05); however, these diets did not restore the performance back to a level equivalent to that of fish offered the basal diet. Meanwhile, fish fed FSBM35T had comparable growth and feed performances to those fed FM. Hematocrit values, total biliary bile acid levels, whole body lipid contents, and tissue taurine concentrations of fish fed SBM35 and SBM50 were the lowest among the treatments, but these parameters were improved by taurine supplementation and FSBM inclusion in the diet. Taurine supplementation increased lipid ADC, and SBM fermentation slightly enhanced both lipid and protein ADCs of the fish. These findings suggest that the combination of FSBM and taurine supplementation is an effective way to improve growth performance, nutrient digestibility, and biological parameters, and that FSBM with taurine supplementation can replace 35% of fish meal in pompano diets without any negative effects on growth and feed performances in a long-term feeding period.     

Study of the optimum ideal protein level for weaned piglets

The amount of ideal protein, represented by the first limiting valine (Val), for optimising the growth performances of weaned hybrid piglets was studied. Feeds were formulated based on the ideal protein concept and on a constant essential/nonessential amino acid (AA) ratio and net energy (NE) level. The animal performance trial was composed of five dietary treatments ranging from 0.57 to 0.81% calculated apparent (app.) ileal (il.) digestible (dig.) Val. The piglets, male and female in equal numbers (11 replicates x 6 piglets/pen x 5 treatments) entered the trial at about 4 weeks old (average live weight 8.1 kg). The piglets were a cross product of Piétrain sire x hybrid dam. Feed intake and weight were recorded every two weeks until the end of the trial at 10 weeks of age (average live weight 20.6 kg). The requirement was expressed in st. il. dig. AA-units, as this unit approaches available AA better than app. il. dig. AA. The standardised (st.) il. AA digestibility coefficients (DCAA) were determined for two feeds, close to the animal performance optima, in a digestion trial with four T-cannulated piglets of approximately 6 weeks old. The feed independent endogenous nitrogen excretion was measured with a protein-free feed; although this technique underestimates the actual endogenous N-losses, it provides a reasonable estimate of basal endogenous N-losses. The determined st. il. DCAA were lower than the calculated st. il. DCAA, based on the CVB (2000); this might be linked to the higher than expected crude fibre content of the experimental feeds. The Val-requirement necessary to optimise ADG and FCR was similar and amounted 0.70% st. il. dig. Val, which corresponded with a st. il. dig. Lys-level of 1.03%.     

Comparison of low-glycoalkaloid potato protein and fish meal as protein sources for weaner piglets

A total of 32 weaner piglets (Landrace×Yorkshire) with an average initial body weight of 9.6±1.2 kg, and 29.8±2.7 days of age, were used in a 28-day growth assay to compare low-glycoalkaloid potato protein with fish meal as the main protein source. The piglets were housed pair-wise in pens and were fed semi-ad libitum. During feeding the piglets were separated allowing individual feeding within the pen. Four diets were tested with varying proportions of a high quality fish meal (F) and low-glycoalkaloid potato protein (P): diet A (10% F); diet B (5% F and 5% P); diet C (2.5% F and 7.5% P) and diet D (10% P). On average, in weeks 1–4, the piglets on diets C and D had higher feed intakes (17%; P<0.01) and daily weight gains (18%; P<0.05) than the piglets on diets A and B. There was no effect of diet (P>0.05) on feed conversion. It can be concluded from the present study that low-glycoalkaloid potato protein can completely replace high quality fish meal in diets for weaner pigs. The improved feed intake and daily gain with increasing inclusion suggests that low-glycoalkaloid potato protein may be superior to fish meal as a protein source for weaner pigs.