Meat meal in the diet of the early-weaned pig IV. The supplementation of diets with tryptophane,lysine and methionine

Two experiments were conducted with 72 pigs between 28 and 56 days of age to study the effect of tryptophane supplementation on their performance when fed on diets containing wheat and meat meal.In the first experiment, pigs were fed on a basal diet (Diet 1) or on the same diet supplemented with calcium dihydrogen phosphate (Diet 2), bone meal (Diet 3) or bone meal plus tryptophane (Diet 4), all to 3.1% calcium. The weight gains of the pigs (315 g day^?1) fed on Diet 3 were significantly lower than that of the pigs fed on the other three diets (363 g day^?1). The feed conversion ratios showed a similar trend. Diet 3 contained 0.16% tryptophane while the other diets contained 0.18–0.19% tryptophane. The crude protein, lysine and methionine contents of all diets were similar.In the second experiment, a basal diet containing meat meal and bone meal was supplemented with tryptophane, lysine plus methionine or all three amino acids. Feed intake was increased by all amino acid supplements. Weight gains were improved significantly (57%) by the addition of all three amino acids to the diets, but the improvements due to tryptophane alone (28%) or methionine plus lysine (35%) were not significant. Tryptophane supplementation alone or with lysine plus methionine increased the nitrogen retention of the pigs.It was concluded that the requirement for tryptophane of pigs between 28 and 56 days of age was greater than 0.16% of diets containing wheat and meat meal.     

Meat meal in the diet of the early-weaned pig. III. Meat meal quality and the processing of meat meals

Fifteen samples of normal meat meals were shown to contain 42.2–54.6% crude protein, 8.2–15.8% calcium, 0.20–0.49% tryptophane, 0.22–0.63% cystine and 2.38–3.39% lysine.Two experiments were conducted with 72 pigs between 4 and 8 weeks of age to study the effect of meat meal quality on performance.In the first experiment, increasing the final temperature during the processing of meat meals from 115 to 155°C reduced weight gains by 17% and increased feed conversion ratio by 9%. This experiment also showed that meat meal made from soft offal gave weight gains 7% greater than those of pigs fed on meat meal from hard offal.In the second experiment, five different meat meals were included in the diets of young pigs so that all diets contained about 20% crude protein, and dicalcium phosphate was added so that the calcium content of all diets was 2.8%. The five meat meals resulted in significant differences in the growth of pigs, and this may have been related to their tryptophane and cystine content.     

Meat meal in the diet of the early-weaned pig. I. A comparison of meat meal and soya bean meal

Seventy-two pigs, initially weighing 4–5 kg, were fed on wheat-based diets supplemented with soya bean meal and/or meat meal in two experiments each of 4 weeks' duration.In the first experiment, 0, 25, 50 or 100% replacement of soya bean meal protein supplement with meat meal was associated with a linear decrease in weight gains (341-280 g/d), a linear increase in feed conversion ratios (1.64–2.35) and a linear decrease in apparent digestibility of dry matter (80.1–73.4%). There was no change in the apparent digestibility of nitrogen.In the second experiment, bone meal was added to provide 0.80, 1.55 and 3.05% calcium in diets in which the protein supplements were either soya bean meal or meat meal. The addition of bone meal to the diets containing soya bean meal did not affect the performance of the pigs, but it caused a linear decrease in the apparent digestibility of dry matter, nitrogen and calcium. The addition of bone meal to the diet containing meat meal reduced the feed intakes of the pigs from 617 to 516 g/d and the weight gains from 414 to 324 g/d.Weight gains of pigs were similar when their diets contained soya bean meal or meat meal as the protein supplement in the second experiment when the calcium content of the diets was 0.8%. The meat meal included in the diet was manufactured from soft offal.     

Lupin-seed meal (Lupinus albus cv. Hamburg) as a source of protein for growing pigs

Two experiments were performed to evaluate Lupinus albus cv. Hamburg as a source of protein for growing pigs. The first was in a factorial design, involving two levels of feeding (restricted and ad libitum) and five isocaloric, isonitrogenous diets (0, 10.3, 20.7 and 31% Hamburg, and 31% Hamburg supplemented with 0.20% synthetic L-lysine). The growth performance of pigs from 22 to 70 kg live weight was unaffected by 10.3% Hamburg replacing soya-bean meal and meat and bone meal, but at higher levels both growth rate and feed conversion efficiency were significantly depressed. Feed intake was not significantly affected by the level of Hamburg, but dressing percentage decreased significantly from 84.3 to 80.2% as the proportion of Hamburg was increased from 0 to 31%. The addition of synthetic lysine to the 31% Hamburg diet improved feed conversion efficiency, but not to the level of the diet containing no Hamburg.Hamburg contained 2100 mg/kg manganese and the effects of levels of manganese from 72 to 1330 mg/kg on pig performance between 20 and 55 kg live weight were studied in the second experiment. Up to 1330 mg/kg manganese in the diet did not affect the growth performance or carcass quality of pigs. In both experiments, the growth performance of pigs given 31 or 33% Hamburg diets, each supplemented with 0.20% synthetic L-lysine, was lower than that of pigs receiving diets without Hamburg.The digestible energy content and alkaloid content of Hamburg were 18.2 (SE ± 0.38) MJ/kg dry matter and 0.018%, respectively.     

饲料中土豆蛋白替代鱼粉对虹鳟摄食率、消化率和生长的影响

通过生长试验探讨了饲料中土豆蛋白浓缩物替代鱼粉后对虹鳟摄食率,消化率,生长和饲料利用的影响,对照饲料全部鱼粉为蛋白源,其它饲料分别含土豆蛋白２．２％,５．６％,８．９％和１１．１％,另一饲料含５．６％,土豆蛋白和１．７％蛋氨酸,在１２℃下饲养４周,试验结果表明,随着饲料中土豆蛋白使用比例的增加,虹鳟的摄食率下降,饲料的干物质,蛋白和灰分的表现消化率上升,脂肪的表现消化率无显著影响,当饲料中含５．６     

Effects of dietary protein and amino acid levels on the expression of selected cationic amino acid transporters and serum amino acid concentration in growing pigs

The absorption of lysine is facilitated by leucine, but there is no information regarding the effect of crude protein, lysine and leucine levels on the expression of cationic amino acid transporters in pigs. Therefore, an experiment was conducted with 20 pigs (14.9 +/- 0.62 kg initial body weight) to evaluate the effect of two protein levels, and the content of lysine, threonine, methionine and leucine in low crude protein diets on the expression of b(0,+) and CAT-1 mRNA in jejunum, Longissimus dorsi and Semitendinosus muscles and serum concentration of amino acids. Treatments were as follows: (i) wheat-soybean meal diet, 20% crude protein (Control); (ii) wheat diet deficient in lysine, threonine and methionine (Basal diet); (iii) Basal diet plus 0.70% L-lysine, 0.27% L-threonine, 0.10% DL-methionine (Diet LTM); (iv) Diet LTM plus 0.80% L-leucine (Diet LTM + Leu). Despite the Basal diet, all diets were formulated to meet the requirements of lysine, threonine and methionine; Diet LTM + Leu supplied 60% excess of leucine. The addition of lysine, threonine and methionine in Diet LTM increased the expression of b(0,+) in jejunum and CAT-1 in the Semitendinosus and Longissiums muscles and decreased CAT-1 in jejunum; the serum concentration of lysine was also increased (p < 0.01). Further addition of L-leucine (Diet LTM + Leu) decreased the b(0,+) expression in jejunum and CAT-1 in the Longissimus dorsi muscle (p < 0.05), increased the serum concentration ofleucine and arginine and decreased the concentration of isoleucine (p < 0.05). Pigs fed the Control diet expressed less b(0,+) in jejunum, and CAT-1 in the Semitendinosus and Longissiums muscles expressed more CAT-1 in jejunum (p < 0.05) and had lower serum concentration ofisoleucine, leucine and valine (p < 0.05), but higher lysine concentrations (p < 0.01) than those fed Diet LTM. These results indicated that both, the level and the source of dietary amino acids, affect the expression of cationic amino acid transporters in pigs fed wheat-based diets.     

Treatment of the haem fraction of abattoir blood with formic acid to produce a solid state,low dry matter protein supplement for use in finishing-pig diets

Commercially produced haem fraction of abattoir blood with a dry matter content of 35% was treated with formic acid of 80–85% purity at the rate of 3:100 (v/v) which transformed the “haem” from a liquid to a solid state and reduced pH from 7.2 to 3.6. The product was included at approximately 5% of the dietary dry matter for pigs over the live weight range 33–80 kg. In one experiment the diet containing the haem was compared with diets containing either 7 or 10% herring meal on an air dry basis. The pigs on the 10% herring meal diet grew slightly, but non-significantly, faster and more efficiently than pigs on the other two diets. The carcases of the pigs on the haem diet contained less lean and more fat than those on the herring meal diets, apparently because of dietary deficiencies of isoleucine and methionine + cystine. In the second experiment, diets with and without the haem fraction were formulated by linear programme taking ingredient costs into account. The performance and carcase composition of pigs on the haem diet were equal to or better than those on the control diet.The total lysine content of the haem fraction of abattoir blood treated with formic acid was 115 g/kg dry matter with an availability (1-fluoro-2,4-dinitrobenzene-reactive lysine) of 86%. In relation to the requirements of the finishing pig the limiting amino acids appear to be isoleucine and methionine + cystine.     

Use of alternative protein sources for fishmeal replacement in the diet of largemouth bass (Micropterus salmoides). Part II: effects of supplementation with methionine or taurine on growth,feed utilization,and health

Fishmeal has long been a staple protein feedstuff for fish, but its global shortage and high price have prompted its replacement with alternative sustainable sources. In this experiment involving largemouth bass (a carnivorous fish), a new mixture of feedstuffs (45% poultry byproduct meal, 30% soybean meal, 15% blood meal, and 10% krill shrimp meal) was added to low (14.5%) fishmeal diets along with 0.0%, 0.5% taurine, 0.5% methionine, or 0.5% taurine plus 0.5% methionine (dry matter basis). The positive control diet [65.3% fishmeal (46% crude protein on dry matter basis)] and all low-fishmeal diets contained 40% true protein and 10% lipids. There were 3 tanks per treatment group (20 fish/tank). Fish with the mean initial body weight of 16.6 g were fed to satiety twice daily. Compared with the unsupplemented low-fishmeal group, supplementing either 0.5% methionine or 0.5% methionine plus 0.5% taurine to the low-fishmeal diet improved (P < 0.05) the growth, feed utilization, retention of dietary protein and lipids, and health of largemouth bass, reduced (P < 0.05) the occurrence of black skin syndrome from ~ 40 to ~ 10%. Histological sections of tissues from the fish with black skin syndrome showed retina degeneration, liver damage, and enteritis in the intestine. Compared with methionine supplementation, supplementing 0.5% taurine alone to the low-fishmeal diet did not affect the growth or feed efficiency of fish and had less beneficial effects (P < 0.05) on ameliorating the black skin syndrome. These results indicated that: (a) the basal low-fishmeal diet was inadequate in methionine or taurine; and (b) dietary supplementation with methionine was an effective method to improve the growth performance, feed efficiency, and health of largemouth bass. Further studies are warranted to understand the pathogenesis of the black skin syndrome in largemouth bass.

     

Cabbage (Brassica oleracea) in the diet of growing—Finishing pigs

Comminuted cabbage (Variety Drumhead) was used in diets for growing pigs and contained in dry matter (DM), 18 MJ/kg, 23% crude protein, 7.9% true protein, 0.76% total lysine, 0.47% methionine + cystine, 14.2% acid detergent fibre and 13.2% ash.Ninety pigs were raised from an initial live weight of 57 kg either on a diet containing 80.5% barley and 18% soya bean meal on a DM basis, or on diets in which cabbage DM replaced either 15 or 30% of the DM from this mixture. The use of cabbage in the diet at these inclusion levels reduced the rate of carcass-weight gain by 12.2 and 18.5%, respectively, compared with that of the control animals.The potential high yield of nutrients/ha from cabbage, factors which may be affecting the utilization of these nutrients by pigs and the variable chemical composition of this brassica crop, are discussed.     

A nutritional evaluation of buckwheat (Fagopyrum esculentum)

Experiments were conducted with rats, pigs, chickens and laying hens. Buckwheat had a high neutral detergent fibre content of 20%; digestible energy measured with pigs was 11.5 MJ/kg, and a mean metabolizable energy value of 11.0 MJ/kg with poultry. Growth studies with rats and chicks showed that buckwheat in mono-grain diets was superior to cereal grains. However, it was not possible to identify limiting amino acids in buckwheat, and supplementation with fat and protein sources did not promote the growth responses anticipated. Removal of the fibrous hulls from buckwheat by sifting did not increase growth rate, but food conversion was improved.Although chemical analysis indicated that amino acids were adequate to maintain egg production, this was not confirmed in laying trials even when additions of lysine and methionine were made to buckwheat. The most favourable response to buckwheat was achieved in pig-growth studies. Growth rate on an all-buckwheat diet was not different from that on an all-wheat (12% CP) diet but addition of lysine improved growth rate and feed conversion. Addition of 10% meat meal or sunflower meal to buckwheat gave similar growth and feed conversion to those of a commercial grower diet. Amino acid disappearance, measured at the terminal ileum of pigs prepared with re-entrant cannulas, gave values ranging from 90% for methionine to 65% for leucine, although there was substantial variation among pigs.It was apparent that buckwheat as the sole grain source was not suitable for the species examined. Differences in performance between individual animals may be attributed to their capacity to degrade the buckwheat fibre. This may in part explain the variation in the response of individuals to the experimental diets and therefore a tendency to mask responses to the various supplements. It can be concluded from this study that buckwheat as the sole source of energy is unsuitable for pigs and poultry even though in the diets of pigs it gave acceptable growth rate and feed conversion. Some pigs, however, did not take readily to this grain and often took several hours to consume their rations. Poor acceptability, perhaps due to the presence of a toxin or other chemical compounds, appears to be associated with this grain.     

Apparent digestibilities and growth experiments with tilapia (Oreochromis niloticus) fed soybean meal, cottonseed meal and sunflower seed meal

Apparent digestibility and growth experiments with three oil seed by-products, soybean meal, cottonseed meal, and sunflower seed meal, were conducted using tilapia ( Oreochromis niloticus ) with an initial average body weight of 93 ± 5 g and 64 ± 1 g, respectively. The diets were formulated on an isonitrogeneous and isoenergetic basis. During the experimental period the fish were fed 1% and 1.5% of their metabolic body weight (kg^0.8) daily in the digestibility experiment and the growth experiment, respectively. Water temperature was maintained at 26.5 ± 1°C. Apparent digestibilities of the components and the diets were determined using an indirect method, i.e. with HCl-insoluble ash as an indicator. Faeces collection was carried out using a sedimentation technique.
Results of the apparent digestibilities showed that the crude protein, crude fat, as well as the gross energy digestibilities of soybean meal (93.0%, 94.6%, and 77.2%, respectively), were better than those of cottonseed meal (79.4%, 83.2%, and 57.9%, respectively) and sunflower seed meal (89.8%, 82.9%, and 49.3%, respectively). With the exception of the crude protein digestibility, nutrient and gross energy digestibilities of the cottonseed meal were found to be better than that of sunflower seed meal.
Growth experiment results indicated that soybean meal diet groups had inferior growth performance and feed conversion in comparison to the fishmeal control diet or the other test diets at an inclusion level of 32% of the digestible protein. Fish fed cottonseed meal diet and sunflower seed meal diet showed a relatively better, but not significantly different performance than did the fishmeal control diet. Supplementation diets with lysine and methionine did not enhance fish performance.     

Production and egg quality in layers fed organic diets with mussel meal

The first limiting nutrients in typical laying hen diets are the sulphur-containing amino acids and, in particular, methionine. To fulfil the birds' recommended requirement, conventional diets are supplemented with synthetic methionine. As this is not allowed in organic production it becomes very important to have access to alternative high-quality protein feed ingredients. An experiment was performed to evaluate the possibility to compose a diet with 100% organically approved feed ingredients using mussel meal as a major source of methionine. The experiment included 678 Lohman Selected Leghorn (LSL) and 678 Hyline White, W-98, layers during 20 to 72 weeks of age. There were 12 aviary pens with 113 birds in each. The birds were fed one of the two experimental diets containing either 3.5% or 7% dried mussel meat meal or a commercial organic diet from a Swedish feed manufacturer for comparison. Production and mortality were recorded daily per group, and egg weight was recorded once weekly. At 33, 55 and 70 weeks, 10 eggs from each treatment group were collected and analysed for internal egg quality. Diets had no significant effect on laying percentage, egg mass, feed intake, feed conversion ratio, mortality, bird live weight or proportion misplaced, cracked or dirty eggs. Egg quality, that is, shell deformation, shell breaking strength, albumen height, shell percentage and proportion of blood and meat spots were also unaffected. There was a significant difference in egg yolk pigmentation, that is, the egg yolk was more coloured when feeding 7% mussel meal compared with the other diets. Hyline hens had lower feed intake and laying percentage, and higher egg weight, but lower egg mass production than LSL birds. The age of the birds influenced all egg quality traits except for meat and blood spots. The dry matter of the excreta was significantly lower for both genotypes fed the 7% mussel meal diet. These results indicate that mussels may be a high-quality protein source and may replace fishmeal in organic diets for layers.     

Swedes (Brassica napus) for growing pigs: Chemical composition and use as a replacement for barley in the diet

Macerated swedes (variety Balmoral) were used in diets for growing pigs and contained in dry matter (DM), gross energy 18.6 MJ/kg, crude protein 12.8%, true protein 5.0%, total lysine 0.40%, methionine + cystine 0.26%, total soluble sugars 40.8%, acid-detergent fibre 20.6% and ash 10.9%.One hundred pigs were grown from a mean live weight of 56 kg on either a control diet, containing 89% barley and 9% soya bean meal on a DM basis, or on diets in which swede DM replaced 20 or 40% of barley DM. The results suggest that for equivalent carcass growth approximately 1.5 units of swede DM are required for each unit of barley DM replaced.Swedes are a potentially valuable food, but further investigation is required into factors affecting their nutritive value for pigs, particularly varietal differences, the effect of within-season changes in chemical composition and the utilization of the energy, protein and fibre components of the organic matter.     

Effects of amino acid supplementation on the nutritive quality of fermented linseed meal protein in the diets for rohu, Labeo rohita, fingerlings

A feeding trial was conducted for 8 weeks to examine the effects of partial substitution of fish meal (FM) protein (crude protein content: 58.5%) with linseed meal protein with and without supplemental amino acids in diets for rohu Labeo rohita (Hamilton), fingerlings (mean weight: 1.50 ± 0.3 g). Prior to incorporation into the diets, linseed meal was fermented with lactic acid bacteria ( Lactobacillus acidophilus ) to reduce/eliminate the antinutritional tannin and phytic acid factors. Twelve experimental diets (diets D1–D12) were formulated to replace the FM protein from a reference diet (RD) with linseed meal protein at different levels (four sets of diets, of which each set of three diets contained 25%, 50% and 75% replacement of FM protein by linseed meal protein, respectively). Diets D1–D3 were not supplemented with any amino acid. Lysine was supplemented in diets D4–D6. Diets D7–D9 were supplemented with methionine + cystine (together), and diets D10–D12 contained lysine and methionine + cystine (together). Lysine and methionine + cystine (together) were added to the diets at 5.7% and 3.1% of dietary protein, respectively. The groups of fish fed diets without amino acid supplementation had significantly lower percentages of weight gain, specific growth rate and high feed : gain ratio than the fish groups fed other experimental diets. The addition of lysine and methionine + cystine to the diet in which 50% of the FM protein was replaced by linseed meal protein (diet D11) significantly improved fish performance. The results of the present study suggest that rohu fingerlings can effectively utilize the supplemented amino acids and that linseed meal protein can replace up to 50% of the FM protein in rohu diets if the linseed meal is properly processed (fermented) and supplemented with the lacking amino acids.     

Lysine and arginine requirements of juvenile Asian sea bass (Lates calcarifer)

Two separate experiments were conducted to determine the dietary requirements of juvenile Asian sea bass Lates calcarifer Bloch for lysine and arginine. Fish (average initial weight: lysine experiment, 13.12 ± 0.12 g; arginine experiment, 2.56 ± 0.13 g) were given amino acid test diets for 12 weeks containing fish meal, zein, squid meal, and crystalline amino acids. Each set of isonitrogenous and isocaloric test diets contained graded levels of L ‐lysine or L ‐arginine. The feeding rate in the lysine experiment was at 4–2.5% of the body weight day^?1, while in the arginine experiment it was at 10–4% of the body weight day^?1. The fish (20 per tank, lysine experiment; 15 per tank, arginine experiment) were reared in 500‐L fibreglass tanks with continuous flowthrough sea water at 27 °C and salinity of 31 ppt in the lysine experiment and at 29 °C and salinity of 29 ppt in the arginine experiment. The experiments were in a completely randomized design with two replicates per treatment. Survival was high in fish given adequate lysine or arginine. Mean percentage weight gains were significantly different in fish fed varying levels of lysine or arginine. Fish fed high levels of L ‐arginine suffered high mortalities. No significant differences were obtained in the feed efficiency ratios (FER, g gain g^?1 feed) of fish fed graded lysine, although the values tended to increase as the dietary lysine level was increased up to the requirement level. In contrast, in the arginine experiment, significant differences in FER of fish among treatments were obtained; the highest FER was observed in fish fed the diet containing an optimum arginine level. On the basis of the growth response, survival, and FER, the lysine and arginine requirements of juvenile Asian sea bass were estimated to be 20.6 g kg^?1 dry diet (4.5% protein) and 18.2 g kg^?1 dry diet (3.8% protein), respectively. These data will be useful in the further refinement of practical diet formulations for the Asian sea bass.     

Lupin-seed meal (Lupinus angustifolius cv. Uniwhite) as a protein supplement to barley-based diets for growing pigs

The apparent digestibility coefficients of the energy and nitrogen of diets containing lupin-seed meal (LSM) were similar to those of diets containing fish meal, despite the comparatively high fibre content of the former.In pigs of 25–85 kg, barley-based diets containing LSM as the sole protein concentrate supported similar rates of gain and efficiency of gain as those containing mixtures of LSM and either fish meal or meat and bone meal, and at least as fast and efficient gains as those containing fish meal or meat and bone meal alone as the source of supplementary protein. However, they depressed dressing percentage. Pigs growing from 12 to 25 kg on barley diets in which up to 45% of the supplementary lysine was supplied in the form of LSM grew as well as those given diets containing various mixtures of dried blood, fish meal and skim-milk powder.     

Effects of keratinase supplementation of corn-soybean meal based diets on apparent ileal amino acid digestibility in growing pigs and serum amino acids, cytokines, immunoglobulin levels and loin muscle area in nursery pigs

Two experiments were conducted to evaluate effects of keratinase for growing and nursery pigs. In Exp. 1, six pigs (32.3 +/- 2.8 kg body weight), fitted with a simple T-cannula at the distal ileum, were assigned to one of two 3 x 3 Latin squares involving three periods and three diets including a basal diet and the same diets supplemented with 0, 0.05 or 0.1% keratinase. Dietary keratinase supplementation increased the apparent ileal digestibility of crude protein (CP), arginine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, alanine, glutamic acid and proline (p < 0.05). Digestibility coefficients did not differ between pigs fed 0.05 and 0.1% keratinase. In Exp. 2, 24 piglets weaned at 30 +/- 2 d of age were used in a 2 x 2 factorial design experiment with two CP concentrations (19 vs. 22%) and two levels of keratinase supplementation (0 vs. 0.05%). Keratinase supplementation increased (p < 0.05) average daily gain, serum arginine concentration and loin muscle area but decreased (p < 0.05) serum interleukin-10 concentrations. The reduction in dietary CP level decreased (p < 0.05) serum urea nitrogen concentrations, isoleucine, serine and proline concentrations, but increased serum arginine concentrations. Few interactions between keratinase supplementation and dietary CP concentration were observed. This study indicated that dietary keratinase supplementation improved apparent ileal amino acid digestibility for growing pigs and had a positive effect on weight gain, immune response and loin muscle area for nursery pigs.     

Symposium mit internationaler Beteiligung vom 27.-29. Oktober 1981 in Dresden

Two feeding trials were performed on rainbow trout of mean initial weights of 40 and 50 g and lasting for 12 and 14 weeks, respectively. In trial 1, diets contained per kg 300 g fish meal and varying proportions of gelatinized maize starch plus either casein or hydrolyzed feather meal. Dietary crude protein content varied from about 27 to about 53%. In trial 2, all diets had about 45% crude protein. Fish meal (300 g/kg) was replaced in 3 steps by hydrolyzed feather meal either without or with supplementation of L‐ lysine‐HC1 and/or DL‐methionine.

In trial 1, efficiency of utilization of digestible energy (DE) rose from 38 to 50% when the ratio digestible crude protein (DCP)/DE was increased from about 11 to 17 g/MJ irrespective of the source of additional DCP, but did not further increase at higher ratios DCP/DE. Efficiency of utilization of DCP was about 50% as long as the ratio DCP/DE did not exceed 17 g/MJ.

With progressing replacement of fish meal by hydrolyzed feather meal, efficiencies of utilization of DE as well as of DCP were reduced, the respective rates of reduction being about halved by supplementing lysine with no effect of supplementing methionine.     

Sulphur amino acid requirement of juvenile Asian sea bass Lates calcarifer

The dietary requirement of juvenile Asian sea bass Lates calcarifer Bloch for total sulphur amino acids was studied. Fish (average initial weight of 2.59 ± 0.08 g) were reared in twelve 500 L fibreglass tanks provided with flow-through seawater at 26°C and salinity of 31 p.p.t. for 12 weeks. They were fed semi-purified test diets containing 6.2, 7.2, 8.1, 9.0, 10.8, or 12.6 g methionine kg⁻¹ dry diet and a basal level of 3.1 g cystine kg⁻¹ dry diet. The mean crude protein of the diets (containing defatted Peruvian fishmeal, squid meal, soybean meal, and free amino acid mixture to simulate the pattern of hydrolysed sea bass protein) was 46.02%. The crude fat content of the diets was 10.51% from a 1 : 1 mixture of cod liver oil and soybean oil. Survival was 100% in all treatments. On the basis of the growth response, the total sulphur amino acid requirement of juvenile Asian sea bass was estimated to be 13.4 g kg⁻¹ dry diet (2.9% of protein). Fish fed low levels of l -methionine had significantly lower weight gains and feed efficiency ratios as well as slightly higher hepatosomatic indices. No nutritional deficiency signs were observed other than growth depression in fish fed on diets that were low in methionine. This information is valuable in further refinement of formulations of practical diets for the Asian sea bass.     

Effect of avilamycin and tylosin on the metabolizable energy in growing and finishing pigs

In two metabolism trials with growing and finishing pigs the influence of the antibiotic feed additives Avilamycin and Tylosin on the metabolizable energy was investigated at different levels of dietary protein content. In the first experiment (growing pigs) the antibiotics were supplied at levels of 0 mg/kg, 40 mg/kg Avilamycin and 40 mg/kg Tylosin to diets containing 18.5%, 17.5%, 16.5% and 14.0% of crude protein. In the second experiment (finishing pigs) 0 mg/kg antibiotics, 20 mg/kg Avilamycin and 20 mg/kg Tylosin were used in diets containing 16.5% and 14.0% of crude protein. The body weight of the animals averaged 46 kg (growing pigs) and 68 kg (finishing pigs).

In growing pigs the supplementation of Tylosin increased the digestibility of dry matter and energy at 1 percentage unit each, while in finishing pigs no effects were observed. Since the urinary energy excretion was not affected by antibiotics, there was only in Tylosin treated growing pigs a slight rise in dietary contents of metabolizable energy by 1.6%. The reduction of the dietary protein content resulted in increased digestibility of dry matter and energy, reduced urinary energy excretions and increased dietary contents of metabolizable energy.