Meat meal in the diet of the early-weaned pig. II. Amino acid supplementation

One hundred and twenty pigs, initially 4–5 kg liveweight, were fed on wheat-based diets supplemented with meat meal and amino acids in two experiments, each of 4 weeks duration.In the first experiment, the supplementation of a normal meat meal diet with lysine and methionine increased the feed intake and weight gains of the pigs by 15 and 18%, respectively. Nitrogen retention was increased by 30%. Tryptophane gave a similar response to lysine and methionine.In the second experiment, a 21% crude protein basal diet was similar to the basal diet of the first experiment but it contained 1.02% lysine and 0.50% methionine plus cystine, compared to 0.90 and 0.51%, respectively, in the first experiment. Lysine and methionine supplementation of the diet did not significantly improve the performance of the pigs in the second experiment, but the supplementation of the diets with 0.08% tryptophane and lysine and methionine increased weight gains and feed intakes and decreased urea content of the blood plasma. The 21% crude protein diet contained 0.15% tryptophane.Increasing the crude protein content of diets from 18 to 24% by increasing their meat meal content increased the daily weight gains from 190 to 276 g.     

Enumeration and activity of cellulolytic bacteria from gestating swine fed various levels of dietary fiber

Cellulolytic bacteria were enumerated and cellulase activity was determined over a 98-day period from fecal samples of gestating swine fed various levels and sources of fiber. The diets, each fed to five pigs, were a corn-soybean control, 20% corn cobs, and 40 and 96% alfalfa meal. Fecal samples were collected from all pigs on days 0, 5, 14, 21, 35, 49, 70, and 98. Overall, the most probable number of cellulolytic bacteria from pigs fed the control, 20% corn cobs, and 40 and 96% alfalfa meal was 23.3 X 10(8), 15.2 X 10(8), 45.1 X 10(8), and 52.5 X 10(8) per g (dry weight) of fecal sample, respectively. Enumeration of cellulolytic bacteria by counting zones of clearing in roll tubes, as compared with the most probable number procedure, accounted for only 1.1 and 17.0% of the cellulolytic bacteria, respectively, from pigs fed the control or 96% alfalfa meal diet. Cellulolytic bacteria (most probable number) on days 70 and 98 accounted for 4.1 and 10.0% of the viable count for the pigs fed the control and 96% alfalfa meal diets, respectively. The viable count was not different between pigs fed the control and 96% alfalfa meal diets. The overall mean cellulolytic activity (milligrams of glucose released from carboxymethyl cellulose per gram [dry weight] fecal sample per 30 min was 17.0, 19.9, 23.8, and 20.6, respectively, for the control, 20% corn cobs, and 40 and 96% alfalfa meal diets. The results indicate that the cellulolytic flora can be increased by prolonged feeding of high-fiber diets and may represent 10% of the culturable flora.     

Enumeration and activity of cellulolytic bacteria from gestating swine fed various levels of dietary fiber.

Cellulolytic bacteria were enumerated and cellulase activity was determined over a 98-day period from fecal samples of gestating swine fed various levels and sources of fiber. The diets, each fed to five pigs, were a corn-soybean control, 20% corn cobs, and 40 and 96% alfalfa meal. Fecal samples were collected from all pigs on days 0, 5, 14, 21, 35, 49, 70, and 98. Overall, the most probable number of cellulolytic bacteria from pigs fed the control, 20% corn cobs, and 40 and 96% alfalfa meal was 23.3 X 10(8), 15.2 X 10(8), 45.1 X 10(8), and 52.5 X 10(8) per g (dry weight) of fecal sample, respectively. Enumeration of cellulolytic bacteria by counting zones of clearing in roll tubes, as compared with the most probable number procedure, accounted for only 1.1 and 17.0% of the cellulolytic bacteria, respectively, from pigs fed the control or 96% alfalfa meal diet. Cellulolytic bacteria (most probable number) on days 70 and 98 accounted for 4.1 and 10.0% of the viable count for the pigs fed the control and 96% alfalfa meal diets, respectively. The viable count was not different between pigs fed the control and 96% alfalfa meal diets. The overall mean cellulolytic activity (milligrams of glucose released from carboxymethyl cellulose per gram [dry weight] fecal sample per 30 min was 17.0, 19.9, 23.8, and 20.6, respectively, for the control, 20% corn cobs, and 40 and 96% alfalfa meal diets. The results indicate that the cellulolytic flora can be increased by prolonged feeding of high-fiber diets and may represent 10% of the culturable flora.     

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.     

Nutritive value of spruce muka (foliage) for the growing chick

Three experiments were conducted with broiler type chicks to determine the nutritive value of spruce (Picea glauca) muka for growing birds to 4 weeks of age. Up to 10% of a diet of maize, soya bean meal and fishmeal was replaced with muka, alfalfa meal or cellulose. Growth, feed consumption, mortality and organ: body weight ratios were examined.The addition of muka, untreated or steam distilled, to the basal diet reduced growth except in the case of 2.5% steam distilled muka, for which growth was comparable to that for the basal diet. When the protein content of the basal diet was reduced, up to 5% untreated or steam distilled muka could be introduced without significant growth depression. However, at the 10% level, growth depression was significant (P < 0.05). Pelleting the supplemented diets significantly stimulated growth.Feed consumption was usually depressed by the addition of the supplements to the basal diet. Mortality was not influenced by treatment. Organ: body weight ratios were not influenced by treatment × sex interactions. Muka, cellulose or alfalfa, each incorporated as 10% of the diet, did not influence the organ: body weight ratio of the heart, proventriculus, caeca, spleen or gall bladder. All the experimental feeds increased the size of the remaining components of the digestive tract, as well as the liver and pancreas.     

Diet selection by red-backed voles<Emphasis Type="Italic">Clethrionomys gapperi</Emphasis>

Food supplementation studies often assume that animals will select artificial diets in their natural environment, and that high-protein, high-energy foods are the most appropriate supplement. These assumptions were tested in red-backed volesClethrionomys gapperi Vigors, 1830 using food-choice experiments with sunflower seeds, oats, and commercial diets in the laboratory and field. Preferred level of dietary protein was also examined using isocaloric diets that varied only in protein content (14%, 20% and 30%). Preferences exhibited in the above trials were subsequently examined relative to natural forage. Voles demonstrated a strong preference for sunflower seeds over oats, dried alfalfa, and rabbit, guinea pig, rat and cat food. Voles preferred the 14% protein diet over the 20% and 30% protein diets. Although sunflower seeds contain more than 20% protein, voles consistently preferred this food over natural forage, perhaps because of their high fat and energy content. This indicates that tradeoffs in protein content may be made to maximize energy. We suggest that red-backed voles will select sunflower seeds in their natural environment, and that their preference for low protein likely reflects their herbivorous diet. This study highlights the importance of ana priori understanding of species-specific preferences and requirements when designing food supplementation studies.     

Optimum Ratio of Histidine in the Piglet Ideal Protein Model and Its Effects on Body Metabolism

A 4 ‐ 4 Latin square design was used to determine ileal apparent digestibility of amino acids (AAs) in corn, soybean meal, feather meal and dried whey in young pigs. The data were then to be used in formulating a basal diet for studies on AA metabolism in young pigs. Eight castrates T-cannulated at terminal ileum (average initial body weight 12.5 ± 0.62kg) were divided into 4 groups on the basis of body weight and transferred to individual metabolism crates. They were then fed four experimental diets containing the four feedstuffs to be tested (corn, soybean meal, feather meal and dried whey). The trial lasted 20 days, which included 4 five-day periods for ileal digesta collection. It was found that the digestibility of the AAs was similar to that reported in literature. Based on the findings a basal diet for this research was formulated according to an ideal protein model for the 10 to 20kg piglet, on the basis of digestible AAs and containing 14.13MJ/kg digestible energy, 18.22% crude protein, 1.04% digestible lysine and 0.23% digestible histidine.     

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.     

The IMTA-cultivated Chlorophyta Ulva spp. as a sustainable ingredient in Nile tilapia (Oreochromis niloticus) diets

Increasing levels of a mixture of Ulva spp. produced in an integrated multi-trophic aquaculture (IMTA) system were evaluated in Nile tilapia juveniles for partial replacement of dietary fish meal. A control diet (CTRL) was compared with three experimental diets containing 10 % (U10), 15 % (U15), and 20 % (U20) of Ulva spp. meal. Triplicate groups of fish (13 g initial body weight) were fed each diet for 63 days at 26 °C. Nutrient apparent digestibility coefficients and nitrogen retention efficiency did not vary significantly among diets. By the end of the trial, all groups of fish more than tripled their initial body weight. Specific growth rate and final body weight of U10 diet were similar to CTRL and significantly higher than U15 and U20 diets. Increasing Ulva dietary incorporation levels significantly increased feed conversion ratio (FCR), from 1.0 (CTRL) to 1.4 (U20). Fish fed with U10 diet had the highest protein efficiency ratio and nitrogen retention efficiency allowing this fish to growth and reach a final body weight similar to the CTRL group. Protein content was highest in fish fed with the CTRL diet, whereas the highest lipid content was observed in fish fed with U20 diet. The results show that the incorporation of IMTA-produced Ulva meal in Nile tilapia diets is possible up to 10 % without compromising growth performance, protein utilization, and protein retention of juveniles. The high capacity of Nile tilapia to digest all experimental diets suggests that Ulva meal is a practical partial replacement for fish meal in Nile tilapia diets.     

Marine ash‐products influence growth and feed utilization when Atlantic cod Gadus morhua L. are fed plant‐based diets

Atlantic cod Gadus morhua L. were fed high plant protein diets added to either shrimp‐shell meal or crab‐shell meal. The aims were to investigate if diluting dietary energy would reduce the liver index (HSI) and if marine ash would add value to plant protein‐based diets. Two control diets were used: a high plant protein control diet (PP) with no marine ash addition, and a fishmeal‐based diet (FM) with no marine ash addition. All diets were evaluated in small cod (initial weight 79 ± 15g) and in market‐size cod (initial weight 1579 ± 20 g). Addition of crab‐shell meal up to 20% and shrimp‐shell meal up to 10% did not influence liver size in either small or market‐size cod. An addition of up to 20% crab‐shell meal and 10% shrimp‐shell meal improved growth compared to the PP control diet, and stimulated increased feed intake. However, 10% shrimp‐shell meal and 20% crab‐shell meal diets resulted in a similar intake of energy and protein as the control groups. Increasing shrimp‐shell meal to 20% resulted in reductions in feed intake, fat digestibility and growth, and in altered gut histology. All diets, except the 20% shrimp added diet, resulted in normal ranges of plasma nutrients and blood hematological values, showing good fish health with or without the marine ash addition.     

The effect of exposure to oestrous ewes on rams' sexual behaviour, plasma testosterone concentration and ability to stimulate ovulation in seasonally anoestrous ewes

Ruminants eat a variety of foods from different locations in the environment. While water, cover, social interactions, and predators are all likely to influence choice of foraging location, differences in macronutrient content among forages may also cause ruminants to forage in different locations even during a meal. We hypothesized that lambs forage at locations containing foods that complement their basal diet and meet their nutritional needs. Based on this hypothesis, we predicted that lambs (n=12) fed a basal diet low in protein and high in energy would forage where a high-protein food (Food P) was located, and that lambs (n=12) fed a basal diet low in energy and high in protein would forage where a high-energy food (Food E) was located. Food P was a ground mixture of blood meal (50%), grape pomace (30%), and alfalfa (20%) that contained 47% crude protein (CP) and 2.211 Mcal/kg digestible energy (DE). Food E was a ground mixture of cornstarch (50%), grape pomace (30%), and rolled barley (20%) that contained 6% CP and 3.07 Mcal/kg DE. Food P provided 212 g CP/Mcal DE, whereas Food E provided 20 g CP/Mcal DE. Lambs growing at a moderate rate require 179 g CP and 3.95 Mcal DE. During Trial 1, we determined if lambs foraged to correct a nutrient imbalance, and if they preferred a variety of foods (Foods P and E) to only one food at a location (Food P or E). During Trial 2, we determined if nutrient-imbalanced lambs foraged in the location with the food that corrected the imbalance when the location of the foods changed daily. During Trial 3, lambs were offered familiar foods (Foods P and E) at the location furthest - and novel foods (wheat and soybean meal) at the location nearest - the shelter of their pen. During all three trials, lambs foraged most at the location with the food that contained the highest concentration of the macronutrient lacking in their basal diet, but they always ate some of both foods. Lambs did not feed exclusively at the location with a variety of foods (P and E). Rather, they fed at the location nearest the shelter that contained the macronutrient lacking in their diet. As availability of the food with the needed macronutrient declined in one location, lambs moved to the nearest location that had food with the needed macronutrient. When food that complemented their basal diet was moved to a different location, lambs foraged in the new location. Collectively, these results show that lambs challenged by imbalances in energy or protein selected foods and foraging locations that complemented the nutrient content of their macronutrient imbalanced basal diets.     

Effect of alfalfa meal in diets of laying quails on performance, egg quality and some serum parameters

This study was conducted to investigate the effects of increasing levels of alfalfa meal in the diet of laying quails on egg production, feed consumption, feed efficiency, egg quality, egg yolk cholesterol and selected serum parameters. In this study, 192, 10-week old quails (Coturnix coturnix japonica) were evenly distributed to four groups with four replicates of 12 quails each. The control group was fed a basal diet containing 0% alfalfa meal and the remaining groups received 3, 6 or 9% alfalfa meal for 12 weeks. Live weight, feed consumption, and egg production were recorded and feed efficiency were calculated. Eggs were examined for interior and exterior quality and egg yolk cholesterol content. At the end of the experiment, blood samples were collected and sera were analysed for serum Ca, inorganic P (P(i)), Mg, triglycerides and total cholesterol. Any level of alfalfa meal had no effect on live weight, egg production, feed consumption, feed efficiency, egg weight, and egg yolk index. Six percent and 9% alfalfa meal increased specific gravity of whole egg and eggshell thickness as well as serum P(i) levels. Nine percent alfalfa meal reduced serum triglycerides, total cholesterol levels and egg yolk cholesterol content. The results of this experiment indicated that addition of 9% alfalfa meal into the laying quail diet may improve eggshell quality and reduced serum triglycerides and serum and egg yolk cholesterol without any adverse effect on performance.     

Effect of whole and fractionated dietary alfalfa meal on zearalenone toxicosis and metabolism in rats and swine

Experiments were conducted to determine the mechanism by which dietary alfalfa can protect against zearalenone toxicosis. Female weanling rats were fed semipurified diets containing whole alfalfa meal, fractionated alfalfa meal (fiber, solvent extract, and water extract), and purified components of alfalfa (coumestrol, saponin, lignin, coumestrol + lignin, and saponin + lignin) with and without 250 mg zearalenone/kg of diet. All ingredients were provided for 2 weeks at levels corresponding to those found in diets containing 15 and 25% alfalfa. Yorkshire gilts were fed 15 and 25% alfalfa meal with and without 10 mg zearalenone/kg of diet for 4 weeks. The feeding of zearalenone to rats reduced growth and food consumption but this was overcome by 25% alfalfa. Zearalenone also increased the activity of hepatic 3 alpha-hydroxysteroid dehydrogenase (3 alpha-HSD), the enzyme believed to metabolize zearalenone to alpha- and beta-zearalenols. Dietary alfalfa did not overcome this effect. Alfalfa fiber was the only fraction to partially overcome the growth-depressing effects of zearalenone while the other fractions had no beneficial effects and 3 alpha-HSD was not affected by diet. None of the purified components affected growth parameters or 3 alpha-HSD. The enzyme was also not affected by zearalenone or alfalfa in swine diets. Coumestrol, alpha-zearalenone, and beta-zearalenone were shown to be competitive inhibitors of 3 alpha-HSD in rat liver. It was concluded that the fiber fraction of alfalfa protects against zearalenone toxicity, and that this effect is not dependent on coumestrol or saponin and is not likely mediated through 3 alpha-HSD.     

Effect of Alfalfa Meal in diets of laying quails on performance,egg quality and some serum parameters

This study was conducted to investigate the effects of increasing levels of alfalfa meal in the diet of laying quails on egg production, feed consumption, feed efficiency, egg quality, egg yolk cholesterol and selected serum parameters. In this study, 192, 10-week old quails (Coturnix coturnix japonica) were evenly distributed to four groups with four replicates of 12 quails each. The control group was fed a basal diet containing 0% alfalfa meal and the remaining groups received 3, 6 or 9% alfalfa meal for 12 weeks. Live weight, feed consumption, and egg production were recorded and feed efficiency were calculated. Eggs were examined for interior and exterior quality and egg yolk cholesterol content. At the end of the experiment, blood samples were collected and sera were analysed for serum Ca, inorganic P (P_i), Mg, triglycerides and total cholesterol. Any level of alfalfa meal had no effect on live weight, egg production, feed consumption, feed efficiency, egg weight, and egg yolk index. Six percent and 9% alfalfa meal increased specific gravity of whole egg and eggshell thickness as well as serum P_i levels. Nine percent alfalfa meal reduced serum triglycerides, total cholesterol levels and egg yolk cholesterol content. The results of this experiment indicated that addition of 9% alfalfa meal into the laying quail diet may improve eggshell quality and reduced serum triglycerides and serum and egg yolk cholesterol without any adverse effect on performance.     

饲料中添加苜蓿草粉对草鱼生长、肌肉品质和血清抗氧化指标的影响

为研究苜蓿(Medicago sativa L.)草粉对草鱼(Ctenopharyngodon idella)生长性能、肌肉品质和血清抗氧化指标的影响, 在基础饲料(粗蛋白: 32.0%, 粗脂肪: 4.12%)中分别添加0(对照组)、5%、10%、15%和20%的苜蓿草粉, 饲喂初始体重为(50.04±0.04) g的草鱼, 每个处理3个重复, 进行为期61d的养殖实验。结果表明: (1)与对照组相比, 20%苜蓿组的特定生长率显著降低(P<0.05), 15%苜蓿组的饲料系数和摄食率显著升高(P<0.05)。除5%苜蓿组外, 其余苜蓿添加组草鱼的肥满度显著降低(P<0.05); (2)饲料中添加苜蓿草粉显著降低草鱼肌肉中硫代巴比妥酸值和乳酸含量(P<0.05)。10%和15%苜蓿组草鱼肌肉羟脯氨酸含量显著高于对照组(P<0.05)。此外, 在添加苜蓿草粉后, 草鱼肌肉失水率显著升高(P<0.05)。除20%苜蓿组外, 其余苜蓿添加组草鱼肌肉黏附性显著升高(P<0.05), 草鱼肌肉硬度在10%苜蓿组显著高于对照组(P<0.05); (3)20%苜蓿组草鱼血清过氧化氢酶(CAT)活力显著高于对照组(P<0.05)。与对照组相比, 15%、20%苜蓿组草鱼血清谷胱甘肽过氧化物酶(GSH-PX)活力显著升高, 丙二醛(MDA)含量显著降低(P<0.05)。综上所述, 当苜蓿草粉的添加量不超过15%时, 对草鱼生长性能没有显著性影响, 且能改善草鱼肌肉品质, 提高血清抗氧化能力。因此, 草鱼饲料中苜蓿草粉的添加量不应超过15%。     

Dairy goats adjust their meal patterns to the fibre content of the diet

Few studies have investigated how meal patterns of ruminants are affected by diet fibre content. Dairy goats (N = 32) in late lactation and early gestation were housed in eight groups of four goats, with all combinations of breed (Alpine and Saanen) and lactation number (1 and 2) represented in each group. Each goat had access to its own individual feed trough placed on a weigh scale with data logged automatically. All goats were fed the same total mixed ration (TMR; 30% concentrate and 44.6% NDF in DM) ad libitum for a control period of 22 days. Using the same feed ingredients, half of the groups were then offered a High fibre diet (20% concentrate; 47.3% NDF), and the other half a Low fibre diet (40% concentrate; 41.5% NDF) for a treatment period of 16 days. Daily meal patterns (meal frequency, duration and size, feeding rate, daily feed intake and daily feeding time) were computed for each animal using a meal criterion of 8 min. The last 10 days for each period (control and treatment) were used to calculate individual period means and individual differences between the two periods. During the control period, the goats ate on average 12.1 ± 0.49 meals/day, consuming 4.2 ± 0.10 kg fresh TMR daily. When the ration changed, all measures of feeding behaviour except meal size changed asymmetrically for the goats on the two diets. Goats fed the High fibre diet reduced their meal frequency by 10%, and the first meal after feed distribution lasted 11% longer, leading to a 9% reduction in feeding rate and no significant changes in daily feed intake and daily feeding time. Goats on the Low fibre diet did not significantly change their meal frequency or meal size, but the combined changes nevertheless led to a 9% increase in daily feed intake. On the Low fibre diet, goats were able to increase their feeding rate by a third, leading to a reduction in meal durations, thus reducing daily feeding time by 13%. Goats adapt their feeding behaviour to the fibre proportion of the offered diet, with more changes when fibre content is lowered, which needs to be taken into account when comparing phenotypes and adaptability of small ruminants to different diets.     

Effect of replacing different levels of dietary fishmeal with Jatropha curcas kernel meal on the development of Nile tilapia Oreochromis niloticus (Linnaeus, 1758)

The present trial tested the applicability of Jatropha curcas kernel meal (JKM) as a protein source in diets for Nile tilapia (Oreochromis niloticus) in terms of growth and body composition. Four diets were produced replacing 0% (Control), 50% (J50), 75% (J75) and 100% (J100) of fishmeal with JKM. In a fifth diet, 70% of fishmeal was replaced by JKM, and another 20% replaced by blood meal to minimize crystalline lysine addition. Body mass gain of fish fed the control diet was significantly higher than in all other treatments. However, specific growth rate (SGR) and feed conversion ratio (FCR) were not significantly different between diets J50, J75 and the control. Fish fed the control diet had a lower body protein content, but higher body fat and energy content than fish fed the JKM‐based diets. An adaptation of fish fed diets J50, J75 and J100 could also be observed, as these diets showed worse FCR‐values over most of the first three quarters of the experiment and equal (or in the case of J75, even significantly better) FCR‐values over the final 2 weeks. Despite slightly slower growth, JKM should be further included in the search of alternative plant‐feedstuffs in diets for tilapia, as the growth observed here for up to 75% replacement of fishmeal was very promising.     

The red alga Porphyra dioica as a fish-feed ingredient for rainbow trout (Oncorhynchus mykiss): effects on growth, feed efficiency, and carcass composition

Porphyra dioica meal was added at levels of 5, 10 and 15% to a diet for rainbow trout formulated to be isonitrogenous and isolipidic. The control diet was a commercial trout diet without seaweed meal. The experimental groups were fed in triplicate for 12.5 weeks, during which fish weight increased on average from 107–261 g. Seaweed meal inclusion did not affect significantly weight gain (WG), specific growth rate (SGR), feed efficiency (FE), protein efficiency ratio (PER) and apparent digestibility coefficient of the dry matter (ADC_dm) for any of the diets. Voluntary feed intake (VFI) increased for all seaweed diets compared to the control diet but not significantly (P?>?0.05). Final weight (FW) was significantly smaller for the 15% P. dioica inclusion and hepatosomatic index (HSI) for the 10% and 15% inclusion. Carcass protein content increased for all three experimental diets, and was significantly higher for the diet with 10% seaweed inclusion. Rainbow trout fed with Porphyra meal presented a dark orange pigmentation of the flesh at the end of the trial, compared to the whitish color from the control fish. These results suggest that P. dioica can effectively be included in diets for rainbow trout up to 10% without significant negative effects on weight gain and growth performance. The pigmentation effect of the fish flesh by adding P. dioica meal to the feed is of a considerable interest to the organic salmon-farming industry.     

The nutritive value of Tower rapeseed meal for swine

Two experiments involving 144 Yorkshire × Lacombe gilts, with an average initial weight of 20 kg, were conducted. In Experiment 1 the gilts were allotted to a control diet containing soya bean meal (SBM) or to diets in which either 50% or all of the supplementary protein was provided by Tower rapeseed meal (RSM). In the second experiment the two diets had either SBM or Tower RSM as the supplementary protein source. In a third diet Tower RSM was supplemented with sufficient lysine to equal the calculated available lysine level of the SBM control diet. In Experiment 1, gilts given the SBM diet grew from 20 to 60 kg significantly faster (P<0.01), and had better feed conversion efficiency (P<0.01), than those given the RSM diets. A 50% replacement of SBM by Tower RSM gave intermediate results. Partial or total replacement of SBM by Tower did not significantly affect the growth rate or feed conversion efficiency of the gilts when growing from 60 to 100 kg liveweight. Serum triiodothyronine (T3) and thyroxine (T4) concentrations of the gilts at 100 kg were lower in pigs fed on the RSM diets but the differences were not significant. In the second experiment, total replacement of SBM by Tower RSM, with or without the addition of lysine, significantly (P<0.001) reduced growth rate and feed conversion efficiency during the growing period (20–60 kg) but did not significantly affect performance during the finishing period (60–90 kg). Serum T3 concentration was not significantly affected by the addition of Tower RSM to the diet but T4 concentrations were significantly reduced (P<0.01). None of the carcass parameters studied were significantly affected by the addition of Tower RSM to the diets.     

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.