Solvent-extracted Soybean Meal Research Articles

Supplementing enzymes to extruded, soybean-based diet improves breakdown of non-starch polysaccharides in rainbow trout (Oncorhynchus mykiss)

Plant-based feed ingredients typically contain remnants of dietary fibres [DF; non-starch polysaccharides (NSP) and lignin] that have various antinutritive effects in carnivorous fish. Exogenous enzymes have been shown to improve the apparent digestibility coefficients (ADC) of plant-based diets presumably by assisting in the breakdown of NSP. This study examined the effects on NSP degradation when supplementing β-glucanase, xylanase, protease or a mix of the three enzymes to an extruded, juvenile rainbow trout (Oncorhynchus mykiss) diet containing 344 g kg−1 de-hulled, solvent-extracted soybean meal (SBM). The NSP content in the non-supplemented control diet and in faecal samples from the dietary treatment groups was analysed to determine the recovery/apparent digestibility of cellulose and total non-cellulosic polysaccharide (T-NCP) sugar monomers. The enzymes had significant, positive effects at the pH range and temperature prevailing in the gastrointestinal tract: β-glucanase improved the ADC of mannose, galactose and uronic acids; xylanase and protease improved the ADC of xylose; and protease furthermore improved the ADC of mannose and uronic acids. There were no effects when supplementing all three enzymes together. In conclusion, exogenous enzymes may potentially be applied to fish feed containing SBM, assisting in the breakdown of NSP and alleviating some of the antinutritive effects.

The effect of dietary soybean meal and soy protein concentrate on the intestinal mucus layer and development of subacute enteritis in Yellowtail Kingfish (Seriola lalandi) at suboptimal water temperature

Solvent-extracted soybean meal (SESBM) has been reported to cause subacute enteritis in certain fish species. Two 34-day experiments investigated the effects of SESBM and soy protein concentrate (SPC) on the intestinal mucus layer and development of subacute enteritis in the hindgut of yellowtail kingfish (Seriola lalandi) at 22 and 18 °C. Fish were fed increasing levels of SESBM (Exp. 1: 0 g kg−1, 100 g kg−1, 200 g kg−1, 300 g kg−1) and SPC (Exp. 2: 0 g kg−1, 200 g kg−1, 300 g kg−1, 400 g kg−1). No visual signs of inflammation in the hindgut were observed in either experiment. However, increasing dietary SESBM significantly reduced mucus layer thickness. Neutral and acidic goblet cell mucin composition increased at 18 and 22 °C, respectively. A significant positive linear relationship was evident between goblet cell number and SESBM inclusion at 18 °C. SPC inclusion and water temperature had no significant effect on mucus layer thickness or mucin composition. However, at 18 °C, goblet cell numbers decreased with SPC inclusion. Results suggest the early stages of subacute enteritis may have been manifesting in SESBM fed fish. In the long term, mucus layer alterations associated with feeding SESBM may compromise fish health. Longer-term studies should investigate the effects of feeding SESBM to yellowtail kingfish, particularly at suboptimal water temperatures.

Effects of trypsin inhibitor and particle size of expeller-extracted soybean meal on broiler live performance and weight of gizzard and pancreas

Soybean meal (SBM) is a co-product that remains after the oil is removed from whole soybeans by either solvent extraction or mechanically pressing soybeans using an expeller. Expeller-extracted soybean meal (ESBM) contains more fat and less protein than solvent-extracted soybean meal (SSBM), but has higher trypsin inhibitors (TI) that limit its inclusion in poultry diets. We hypothesized that increasing the particle size of ESBM could enhance chick tolerance to dietary TI. The experiment consisted of a 2 × 6 factorial arrangement of 2 ESBM particle sizes (coarse, 1,300 µm, and fine, 530 µm) and 6 TI levels (6, 9, 12, 15, 18, and 21 TIU/mg). A total of 672 male broiler chicks was randomly assigned among the 12 treatment combinations with 8 replicates per combination. The birds were provided with 1 kg/bird of starter diet in a crumble form. The pancreas and gizzard were excised and weighed at 16 d of age and organ weights relative to BW calculated. Feed consumption, BW, and feed conversion ratio (FCR) were determined at 7 and 14 d of age. Increasing TI level produced a quadratic effect (P < 0.01) on BW and FCR at 14 d of age. The best performance was obtained when chicks were fed diets containing ESBM at intermediate TI levels. Increasing the particle size of the ESBM from 530 to 1,300 µm improved BW and feed intake (P < 0.01) without affecting FCR. The relative weight of the pancreas increased linearly as TI level increased (P < 0.001). The results of this study indicated that chicks performed better when fed coarse ESBM at an intermediate TI level.

Replacement of Fish Meal with Soybean Meal, Alone or in Combination with Distiller's Dried Grains with Solubles in Practical Diets for Pacific White Shrimp, Litopenaeus vannamei, Grown in a Clear‐Water Culture System

AbstractThe objective of this study was to evaluate inclusion of distiller's dried grains with solubles (DDGS) as partial replacement of commercial, solvent‐extracted soybean meal (SBM) in fish meal‐free diets for Pacific white shrimp, Litopenaeus vannamei. Aquaria connected to a recirculating biofiltration system were utilized to evaluate growth, survival, and feed conversion of shrimp during the 8‐wk feeding trial. Each 110‐L aquarium was stocked with 15 shrimp (mean individual weight 0.99 g) and fed one of five diets: a diet containing 20% fish meal (FM), which served as the control (Diet 1); a diet containing 0% FM and 52.5% SBM (Diet 2); and diets containing 0% FM and either 10, 20, or 30% DDGS as partial replacement of SBM (Diets 3, 4, and 5, respectively). Shrimp were fed according to a pre‐determined feeding chart five times daily (0730, 1030, 1330, 1630, and 1930 h) and there were three replicates per dietary treatment. The results from the feeding trial demonstrated that final weight, weight gain (g), and percentage weight gain were significantly higher (P &lt; 0.05) for shrimp fed Diet 1 (10.96 g, 10.01 g, and 1051%, respectively) compared to shrimp fed diets containing DDGS; however, shrimp fed diets containing DDGS had similar (P &gt; 0.05) final weight, weight gain (g), and percentage weight gain as shrimp fed a diet containing 0% FM and 52.5% SBM (Diet 2). Feed conversion ratio (FCR) of shrimp fed Diet 1 (2.84) was significantly lower (P &lt; 0.05) compared to shrimp fed any other diet. Survival (%) was not different (P &gt; 0.05) among treatments and averaged 77.3% for the study. This study demonstrated that practical shrimp diets containing no FM had an adverse impact on growth performance of white shrimp when grown in a clear‐water system and that further research is needed to refine diet formulations when culturing shrimp in these systems when attempting to feed a diet without FM.

The effects of soybean press cake on productive traits and meat quality of Italian heavy pigs intended for Parma Ham production

Sixty castrated male pigs (initial average body weight (BW) of 26 kg) were allotted to two experimental groups, one of which was fed a diet containing solvent extracted (SE) soybean meal, whereas the other received a diet in which SE soybean meal was entirely replaced by soybean press cake (CAKE). Pigs were slaughtered at about 160 kg body weight, according to the rules for Parma Ham production. The soybean source did not significantly (P &gt; 0.05) affect the growth traits (average daily gain (ADG) and feed conversion ratio (FCR), slaughtering parameters (dressing out, lean meat percentage and lean cuts yields) or meat quality (pH, colour and water holding capacity). From a human nutrition standpoint, soybean press cake favourably influenced fatty acids composition of the subcutaneous fat of the thighs. Heavy pigs receiving soybean press cake showed, in fact, a significantly (P &lt; 0.001) lower relative content of saturated fatty acids (SFA) and an increased (P &lt; 0.05) level of polyunsaturated fatty acids (PUFA) in comparison with animals fed the diet containing SE soybean meal. No negative effects were noted with respect to ham attitude for long-term curing.

Replacement of fishmeal with novel plant feedstuffs in the diet of red drumSciaenops ocellatus: an assessment of nutritional value

This study assessed the nutritional value of corn protein concentrate (Corn-PC), barley protein concentrate (Barley-PC), soy protein concentrate (Soy-PC) and soybean meals [commercially available solvent-extracted soybean meal (SBM), and two new varieties, SBM-209, SBM-3010] in the diet of red drum, Sciaenops ocellatus. Two independent growth trials were conducted to evaluate the replacement of 50% (Trial I, 8 weeks) or 88% (Trial II, 6 weeks) of the protein (solely from menhaden fishmeal) in the control diet (400 g kg−1 CP, 13 or 13.8 MJ kg−1). In both trials, each diet was fed to juvenile red drum (1.5 and 3.3 g initial wt.) in triplicate aquaria connected as a closed recirculating system. Results indicated that Soy-PC and Barley-PC can replace 50% of fishmeal protein while producing fish performance, condition indices and whole-body composition similar to that of the control diet (P > 0.05). However, a significant reduction in growth performance was observed when each of the soybean meals or Barley-PC was used in combination with Soy-PC (100 g kg−1) to replace 88% of fishmeal protein. While high inclusion levels of these plant feedstuffs deserve further evaluation, Soy-PC and Barley-PC can readily replace half of fishmeal protein without adversely affecting growth performance of red drum.

Amino acid digestibility and metabolizable energy of genetically selected soybean products

To determine the ME and amino acid digestibility of 5 soybean meal (SBM) samples, a precision-fed rooster assay and a chick assay were conducted. The 5 samples were cold-pressed (extruded) soybean meals or solvent-extracted (defatted) soybean meal. Of the cold-pressed varieties (unheated), there was an ultra-low trypsin SBM, a low-trypsin SBM, and a heated and unheated commodity SBM. The solvent-extracted SBM was a heated commodity blend. The TME and AME values were compared between each category: cold-pressed and defatted, as well as between the 2 assays. Semipurified diets containing dextrose as the main energy source were formulated to meet the bird's nutrient requirements, with each diet containing a different SBM product. The TME rooster assay was a precision-fed rooster assay in which 5 birds per diet were fasted for 24 h, crop intubated with 35 g of the test diet containing 46.58% cold-pressed or defatted SBM, and excreta was then collected for 48 h. The total aromatic amino acids rooster assay followed the same protocol, but cecectomized birds were used. For the chick assay, 480 one-day-old chicks were fed a standard corn-SBM starter diet until 17 d of age, and on d 18, the chicks were allowed ad libitum access to the SB-dextrose diets. Excreta were collected on d 22, dried, ground, and analyzed for gross energy and CP to determine ME. The SBM samples that were genetically selected to have lower trypsin inhibitor levels and higher protein had higher ME values and increased amino acid digestibility than the commodity cold-pressed SBM samples. Genetic selection of soybeans for certain traits can have positive effects on the ME value and amino acid digestibility for roosters and chicks.

Response of Pacific White Shrimp, Litopenaeus vannamei, to Three Sources of Solvent Extracted Soybean Meal

AbstractThree sources of soybean meal (SBM) were biochemically characterized and evaluated in diets for juvenile Litopenaeus vannamei. Three biological techniques were utilized to evaluate the nutritional quality of the meals including an outdoor growth trial as well as determination of in vivo apparent digestibility and in vitro digestibility including pepsin digestibility (0.0002%), pH Stat degree of hydrolysis, and immobilized digestive enzyme assay (IDEA). The growth trial was conducted over a 10‐wk period using soybean meal as the primary protein source with each meal being included at 54–58% of the diet based on an equal protein inclusion. At the conclusion of the growth trial there were no significant differences between the test diets indicating equivalent biological availability under practical conditions. The in vivo digestibility trial utilized chromic oxide as the inert marker and 70:30 replacement techniques resulted in typical results. Apparent protein digestibility (APD) and apparent energy digestibility (AED) of the diets ranged from 66.8 to 80.2% and 65.4 to 74.7%, respectively. Ingredient digestibility values for protein and energy ranged from 78.8 to 93.5% and 60.5 to 85.0%, respectively. One of the three SBM evaluated had numerically lower protein digestibility and significantly lower energy digestibility than the other two meals.

The use of a soy product in juvenile yellowtail kingfish (Seriola lalandi) feeds at different water temperatures: 1. Solvent extracted soybean meal

Juvenile yellowtail kingfish (Seriola lalandi) were fed four iso-nitrogenous and iso-calorific (digestible basis) experimental diets containing 0, 10, 20 or 30% solvent extracted soybean meal (SESBM) for 34days at optimal (22°C) and suboptimal (18°C) water temperatures to determine the effects of diet and water temperature on growth, feed efficiency, nutrient retention, apparent nutrient digestibility and digestive functions. The substitution of fish meal up to 20% SESBM did not significantly affect the growth of fish. No differences were detected in any of the other parameters measured between 0 and 10% inclusion. However, second-order polynomial regression demonstrated that increasing SESBM had a negative effect on growth performance, feed efficiency, nutrient retention and the apparent nutrient and energy digestibility of diets for yellowtail kingfish. Whole body moisture, crude lipid, ash and gross energy were affected by SESBM in the diet, except protein. The apparent nutrient and energy digestibilities all decreased linearly with increasing SESBM. Digestive enzyme activities in the pyloric caeca were not affected by diet, whereas activities in the foregut and hindgut varied with SESBM inclusion. Fish held at 18°C had significantly reduced growth, feed efficiency and nutrient retention values. The whole body moisture increased at 18°C, while the apparent nutrient and energy digestibilities and whole body protein and gross energy content were lower at 18°C and there was no effect of temperature on whole body total fat or ash content. The impact of temperature on digestive enzyme activities depended on the section of the digestive tract. This study demonstrates that 10% inclusion of SESBM (21.7% fish meal substitution) can be used as a substitute for fish meal in diets for yellowtail kingfish.

Effect of protein supplementation on milk production and metabolism of dairy cows grazing tropical grass

The objectives of this study were to determine if midlactation dairy cows (Bos taurus L.) grazing intensively managed elephantgrass would have their protein requirement met exclusively with the pasture and an energy concentrate, making the use of protein ingredients unnecessary, as well as to determine the dietary crude protein (CP) content that would optimize the efficiency of N utilization (ENU). Thirty-three Holstein and crossbred (Holstein × Jersey) midlactation dairy cows, producing approximately 20kg/d, were grouped within breed into 11 blocks according to milk yield and days in milk. Within blocks, cows were randomly assigned to 1 of 3 treatments and remained in the study for 11 wk. The control treatment contained only finely ground corn, minerals, and vitamins, and it was formulated to be 8.7% CP. Two higher levels of CP (formulated to be 13.4 and 18.1%) were achieved by replacing corn with solvent-extracted soybean meal (SSBM). Pasture was fertilized with 50kg of N/ha after each grazing cycle and averaged 18.5% CP (dry matter basis). No differences were observed in milk yield or milk fat, protein, and casein content or casein yield. In addition, pasture intake was not different among treatments. Milk urea N increased linearly as the concentrate CP content increased. Cows fed the 8.7% CP concentrate had higher ENU. In another experiment, 4 ruminally cannulated Holstein dry cows were used in a metabolism trial designed in a 4×4 Latin square. Cows were fed the same treatments described as well as a fourth treatment with 13.4% CP in the concentrate, in which urea replaced SSBM as the main N source. Ruminal volatile fatty acid concentration and microbial synthesis were not affected by levels or sources of N in the concentrate. Ruminal NH3N content increased as the concentrate CP content increased. Inclusion of SSBM in the concentrate did not increase production and decreased the ENU of midlactation dairy cows grazing on tropical forage. Supplementation of an 8.7% CP concentrate, resulting in a diet with CP levels between 15.3 and 15.7% of dry matter, was sufficient to meet the protein requirements of such milk production, with the highest ENU (18.4%).

Effects of a rumen-protected form of methionine and a methionine analogue on the lactation performance of dairy cows

The objective the present study was to determine the influence of a supplemental methionine analogue, the isopropyl ester of 2-hydroxy-4-(methylthio)-butanoic acid, commercially available as MetaSmart&lt;sup&gt;TM&lt;/sup&gt;, on lactation performance, particularly milk protein production. The effects of this preparation were compared with those of a rumen-protected form of methionine, marketed as Smartamine&lt;sup&gt;TM&lt;/sup&gt; M. Experiments were conducted according to a 3 &amp;times; 3 Latin square design and included 30 high-yielding dairy cows (22&amp;nbsp;Holstein and 8 Czech Fleckvieh) randomly allocated to three balanced groups. Cows were fed a basal diet based on maize silage, lucerne silage, lucerne hay, fresh brewer&amp;rsquo;s grains, and a concentrate mixture in the form of a total mixed ration ad libitum. The diet M was supplemented with MetaSmart&lt;sup&gt;TM&lt;/sup&gt; (42.5 g/day) and diet S was supplemented with Smartamine&lt;sup&gt;TM&lt;/sup&gt; M (19 g/day), while control diet C contained solvent-extracted soybean meal, which was added to achieve required levels of dietary protein. Each period lasted four weeks in total, including three preliminary weeks and one experimental week during which samples of milk and tail vein blood were taken. Supplementation of MetaSmart&lt;sup&gt;TM&lt;/sup&gt; decreased dry matter intake of cows (18.96&amp;nbsp;kg) in contrast to the diet containing Smartamine&lt;sup&gt;TM&lt;/sup&gt; M, for which dry matter intake was the highest (20.48 kg; P&amp;nbsp;&amp;lt; 0.001). Despite decreased dry matter intake, the highest average milk yields were recorded for cows supplemented with MetaSmart&lt;sup&gt;TM &lt;/sup&gt;(31.34 kg), which produced by approximately 1.14&amp;nbsp;kg (P &amp;lt; 0.001) and 0.78&amp;nbsp;kg (P &amp;lt; 0.01) more milk than cows fed diets C and S, respectively. As expressed by greater ratios milk/DMI, FCM/DMI, and ECM/DMI, the feed efficiency was improved in cows supplemented with MetaSmart&lt;sup&gt;TM&lt;/sup&gt;.Both MetaSmart&lt;sup&gt;TM &lt;/sup&gt;and Smartamine&lt;sup&gt;TM&lt;/sup&gt; M dietary supplementation increased milk yield, milk protein concentrations, and yields and increased the prevalence of &amp;beta;-casein fraction in milk protein. &amp;nbsp;

Dietary supplementation of arginine and/or glutamine influences growth performance, immune responses and intestinal morphology of hybrid striped bass (Morone chrysops × Morone saxatilis)

Various studies with fish species indicate that dietary arginine (Arg) and glutamine (Gln) supplementation may support an enhanced performance beyond simply improving weight gain. Therefore, a feeding trial was conducted to determine the effects of dietary Arg or Gln on growth performance, immune responses and intestinal morphology of juvenile hybrid striped bass, Morone chrysops×Morone saxatilis (4.1±0.02g, initial average weight). The basal diet was formulated from menhaden fishmeal and solvent-extracted soybean meal to contain 45% crude protein and 10% lipid. Arginine and Gln were singularly added to the basal diet at either 1% or 2% or both amino acids were added in combination at 1% to formulate experimental diets with adjustments in glycine to maintain all diets iso-nitrogenous. Fish were fed the experimental diets for a period of 8weeks, at the end of which final weight, specific growth rate and feed efficiency were significantly (P<0.05) higher in fish fed diets supplemented with Arg at either 1 or 2%, Gln at 1%, Arg and Gln both at 1%, but not in those fed the diet supplemented with Gln at 2%.Arginine and/or Gln supplementation tended to improve neutrophil oxidative radical production, but not significantly (P>0.05). However, significantly higher serum lysozyme activity was observed in fish fed the diet supplemented with Arg at either 1 or 2% and Gln at 1%. Intracellular superoxide anion production by hybrid striped bass macrophages also tended to increase, while extracellular superoxide anion production was significantly improved by supplementation of Arg at 1% and Gln at either 1 or 2% of diet.Morphometric analyses demonstrated positive effects of both dietary Arg and Gln on histo-morphological measurements in different portions of the gastrointestinal tract of hybrid striped bass. The 1% Arg diet resulted in the greatest increases in size of the chosen enteric structures, but the other four experimental diets also significantly improved the scores for various intestinal portions compared to fish fed the basal diet.Results from the present experiment demonstrate the importance of dietary supplementation of both Arg and Gln in improving growth performance, eliciting positive changes to several components of the innate immune system, and also benefiting the intestinal functionality of hybrid striped bass.

In Vitro assessment of the nutritive value of expanded soybean meal for dairy cattle

Little information is available about the nutritive value of expanded soybean meal, which is produced by expansion of soybeans prior to solvent extraction of the oil. During processing, expanded soybean meal is subjected to additional heat, which might increase the concentration of ruminally undegraded protein. Processing of soybeans with heat during oil extraction could affect lysine availability by increasing ruminally undegraded protein or by impairing intestinal digestion. Our objective was to compare solvent and expanded soybeans with regard to chemical composition and nutritive value for dairy cattle. Samples of expanded soybean meal (n = 14) and solvent-extracted soybean meal (n = 5) were obtained from People's Republic of China to study effects of the expansion process on nutritive value for dairy cattle. Solvent-extracted soybean meal (n = 2) and mechanically extracted (heated) soybean meal (n = 2) from the United States served as references for comparison. Samples were analyzed for crude fat, long-chain fatty acids, crude protein, amino acids, chemically available lysine, in situ ruminal protein degradation, and in vitro intestinal digestibility. No differences were found between solvent-extracted soybean meals from China and expanded soybean meals from China for crude fat, crude protein, amino acids, or chemically available lysine. In situ disappearance of nitrogen, ruminally undegraded protein content, and in vitro intestinal digestion of the ruminally undegraded protein were generally similar between solvent-extracted soybean meals made in China and expanded soybean meals made in China; variation among soybean meals was small. Results indicate that the additional heat from the expansion process was not great enough to affect the nutritive value of soybean meal protein for ruminants. Although expansion may improve the oil extraction process, the impact on the resulting soybean meal is minimal and does not require consideration when formulating ruminant diets.

Evaluation of an expeller-extruded soybean meal for broilers

SUMMARY Any variation in processing soybeans for inclusion in poultry diets requires validation of the ability of the soybean meal to sustain growth performance similar to what is achieved with solvent-extracted soybean meal. Three experiments were conducted to investigate the effect of feeding an expeller-extruded soybean meal vs. a commercial solvent-extracted soybean meal. Growth performance attributable to the source of soybean meal did not differ for 0- to 18-d-old broilers fed 2 levels of Lys (1.0 or 1.3%) and 2 levels of ME (3,000 or 3,300 kcal/kg). Similar growth performance was obtained for broilers fed solvent-extracted soybean meal vs. expellerextruded soybean meal for 0 to 49 d. However, broilers fed the expeller-extruded soybean meal had lower breast meat yield (24.95 vs. 26.30%). True digestibility values determined with adult cecectomized roosters for the expeller-extruded soybean meal indicated digestibility values of 86.6, 83.5, 87.4, 85.5, 86.5, and 86.7 for Lys, Thr, Met, Val, Ile, and Leu, respectively, which are lower than those reported by the NRC for solvent-extracted soybean meal. The feeding value of expeller-extruded soybean meal used in these experiments was similar to that of solventextracted soybean meal; however, consideration must be given to amino acid digestibility to achieve optimal breast meat yield.

Effect of different rumen degradable nitrogen levels on microbial protein synthesis and digestibility in sheep fed on finger millet straw (Eleucine coracana) based diet

Studies were conducted to determine adequate rumen degradable nitrogen (RDN) levels for optimum microbial protein synthesis and digestibility of nutrients in adult Bandur sheep fed on finger millet straw (FMS) based diet. Thirty Bandur sheep were divided into five groups of six animals each using a balanced completely randomized design. Animals in all groups were fed FMS as a basal roughage and solvent-extracted soybean meal (SBM) as a nitrogen source. The sheep in group 1 (G1) were offered FMS for ad libitum intake. Animals in group 2, 3, 4 and 5 (G2, G3, G4 and G5) were supplemented with SBM to provide RDN level of 16.2, 20.7, 24.7 and 26.6g/kg digestible organic matter intake (DOMI) or 24.9, 31.8, 38.1 and 41.0g/kg digestible organic matter apparently digested in the rumen (DOMR) respectively, along with FMS. The daily total dry matter (DM) and organic matter (OM) intakes showed a linear increase (P<0.05) with increasing levels of RDN supplementation. Digestibility coefficients of DM, OM (linear: P<0.01), crude protein (CP), ether extract (EE) (quadratic: P<0.001), neutral detergent fiber (NDF) and acid detergent fiber (ADF) (quadratic: P<0.05) increased as the level of RDN supplementation increased from G1 to G5. The values for total purine derivatives (TPD) excretion (mmol/day and mmol/kgW0.75) (quadratic: P<0.05), the levels of microbial purine absorption and microbial nitrogen supply (MNSg/day, g/kgDOMI and g/kgDOMR) (quadratic: P<0.01) increased, while microbial nitrogen to total urinary nitrogen ratio (MN:UN) decreased (linear: P<0.01) with the increased RDN level, indicating the efficient conversion of RDN into microbial protein synthesis for G2 animals among the RDN supplemented groups. This study indicated that 16gRDN/kgDOMI or 25gRDN/kgDOMR may be adequate for optimum microbial protein synthesis and digestibility of nutrients, thereby improving plane of nutrition in sheep fed on finger millet straw based diet. The additional RDN supplied beyond certain limit (above 16gRDN/kgDOMI or 25gRDN/kgDOMR) may not be beneficial for improving the digestibility of diet especially on straw based diets.

Effects of dietary arginine and glutamine on growth performance, immune responses and intestinal structure of red drum, Sciaenops ocellatus

Both arginine and glutamine play important roles in tissue repair, cell replication and collagen synthesis which impact animal growth and survival. Thus, a 7-week feeding trial was conducted to determine the effects of dietary arginine and glutamine on growth performance, innate immune responses and intestinal structure of juvenile red drum, Sciaenops ocellatus (6.9 ± 0.04 g, initial average weight). Protein in all experimental diets was derived from menhaden fishmeal and dehulled, solvent-extracted soybean meal to provide isonitrogenous (44% crude protein) and isolipidic (10%) diets. The basal diet contained 0.14% glutamine and 1.72% arginine on a dry-matter basis, which exceeds the established dietary requirement of red drum. Experimental diets were prepared by supplementing the basal diet with either arginine at 1% of dry weight, glutamine at 1%, glutamine at 2%, or both arginine and glutamine at 1%, with adjustments in glycine to maintain equal nitrogen among all diets. Feed efficiency was significantly ( P < 0.05) improved by supplementation of glutamine at 2% and the combination of both arginine and glutamine at 1% of diet. Neutrophil oxidative radical production in fish fed the glutamine and/or arginine-supplemented diets was significantly ( P = 0.03) higher compared with that of fish fed the basal diet, with a synergistic effect observed in fish fed the combined arginine–glutamine diet. Significantly ( P < 0.05) higher serum lysozyme activity also was observed in fish fed the diet supplemented with 1% of both arginine and glutamine. Extracellular superoxide anion production by red drum macrophages was significantly ( P < 0.05) higher for fish fed diets with glutamine at either 1 or 2% and the 1% arginine–glutamine combination compared to fish fed the basal diet. Similarly, macrophages from fish fed the diet with glutamine at 2% and the arginine–glutamine combination at 1% produced significantly higher amounts of intracellular superoxide anion. Morphometric analyses – i.e., measurements of enterocyte, microvillus and fold heights – demonstrated positive effects of both dietary glutamine and arginine in different portions (proximal, mid and distal) of the gastrointestinal tract of red drum. In general, fish fed the diet supplemented with 2% glutamine had the greatest increases in magnitude of the chosen structures, although those fed the diet with arginine at 1% also yielded improved scores for some enteric portions. Therefore, results from the present study establish the importance of both dietary arginine and glutamine supplementation in improving feed efficiency, as well as eliciting positive changes to several components of the innate immune system and intestinal functionality of red drum.

Digestibility Characteristics of Selected Feed Ingredients for Developing Bespoke Diets for Nile Tilapia Culture in Europe and North America

The apparent digestibility coefficients of dry matter (ADC DM), protein (ADCp), essential amino acids (ADC EAA), and energy (ADCe) for Nile tilapia of a selected range of animal and plant feed ingredients found in Western European and North American markets were determined. The investigation was able to provide useful data and information as a prelude for effective diet formulation for this fish species. A reference diet was used for the basis of assessing hydrolyzed fish protein concentrate (CPSP), full‐fat soybean meal (FFSBM), solvent‐extracted soybean meal (SESBM), maize gluten meal (MGM), poultry meat meal (PMM), hydrolyzed feather meal (HFM), and spray‐dried hemoglobin meal (SDHM) by substitution. For each major commercial test ingredient, the ADC were as follows: for plant proteins – FFSBM (ADCp 86.99% and ADCe 74.84%), SESBM (ADCp 93.46% and ADCe 82.16), and MGM which was also utilized well by Nile tilapia (ADCp 83.03% and ADCe 82.36%); for animal proteins – PMM (ADCp 69.30% and ADCe 73.47%), HFM (ADCp 45.53% and ADCe 49.11%), and SDHM was highly digested (ADCp 85.79% and ADCe 75.96%). The ADC EAA reflected the same trends as ADCp, and these varied from &gt;87% on average for the EEA in fish meal, &gt;88% for CPSP, &gt;84% for FFSBM, &gt;63% for SESBM, &gt;83% for MGM, and only 61% for PMM, &gt;63% for HFM, and &gt;77% for SDHM. Highest ADC were obtained with SDHM and SESBM among the animal and plant by‐products tested, respectively. These are discussed in the context of practical diets for tilapia.

Influence of poultry meal, meat meal or soybean meal inclusion on weight gain and production characteristics of Australian snapper Pagrus auratus

Two experiments were done to evaluate the effects of poultry meal (PM), meat meal (MM) or solvent-extracted soybean meal (SBM) inclusion on the performance of Australian snapper Pagrus auratus. In each experiment, test feeds were formulated with similar contents of digestible protein (DP) and digestible energy (DE) using previously determined digestibility coefficients for this species. In experiment 1, groups of snapper (initial weight 14 g) were fed 4 feeds containing 360, 480, 610 or 730 g kg−1 PM; 3 feeds containing 345, 320 or 500 g kg−1 MM; 3 feeds containing 420, 600 or 780 g kg−1 SBM. In experiment 2, groups of snapper (initial weight 87 g) were fed 3 extruded test feeds that contained combinations of PM, MM, SBM or blood meal (BM) which replaced all but 600, 250 or 160 g kg−1 of fishmeal in respective diet formulations. Both experiments included a proprietary extruded aquafeed (COM) to benchmark fish performance. In experiment 1, weight gain was highest in snapper fed feeds containing 360, 345 or 420 g kg−1 of PM, MM or SBM, respectively, and was similar (P > 0.05) to snapper fed the COM feed. Nonetheless, weight gain and protein retention efficiency tended to decrease as the amount of each test ingredient was increased. Relative feed intake was not affected by the inclusion level of PM, MM or BM, but declined significantly in snapper fed diets containing 600 or 780 g kg−1 SBM. Feeding behaviour indicated fish found these feeds unpalatable. In experiment 2, the harvest weight of snapper fed the 3 extruded test feeds was similar (P > 0.05), but lower than snapper fed the COM feed (i.e. 234 vs. 256 g). Feed conversion ratio (FCR) was best in snapper fed the COM feed (FCR = 1.53); however, the FCR of snapper fed feeds containing 160 (FCR = 1.66), 250 (FCR = 1.70) or 600 g kg−1 fishmeal (FCR = 1.60) was not different (P > 0.05). Australian snapper will readily accept feeds containing high levels of PM, MM or SBM and feeds containing these ingredients will support rapid weight and protein gain with little affect on whole body composition. In combination, these feed ingredients were able to replace all but 160 g kg−1 of fishmeal in an extruded test feed. As such, they serve as valuable alternatives to fishmeal and extend the manufacturing options available to aquafeed producers.

Development of a practical soy-based diet for California yellowtail, Seriola lalandi

Two feeding trials were conducted to initiate the development of a practical soy-based diet for California yellowtail (YT), Seriola lalandi. The first trial evaluated fish meal (FM), FM + solvent-extracted soybean meal (SBM) or FM + soy protein concentrate (SPC)-based diets and a commercial reference diet (Skretting Marine Grower). Final weights (31.8–67.6 g), per cent gain (492.8–1059.9%) and feed conversion ratio (1.11–1.59) all followed a similar response in that fish offered the commercial diet performed significantly better than fish maintained on the other diets. The second trial was designed to evaluate the replacement of FM with increasing levels of soy protein. The basal diet contained 400 g kg−1 FM and 240 g kg−1 SBM. The FM was then reduced to 300 g kg−1, 200 g kg−1 and 150 g kg−1 of the diet using SPC as the replacement protein. Final weight (41.2–64.1 g) and per cent gain (110.5–226.5%) followed similar trends with decreases in performance as the FM level was reduced. No gross signs of enteritis were noted, indicating that reduced performance was likely due to nutrient deficiencies or palatability problems rather than an allergic response. Results demonstrate that there is potential to develop reduced FM diets for this species using soy protein.

Effect of quantifying peptide release on ruminal protein degradation determined using the inhibitor in vitro system

The aim of this work was to compare use of an o-phthaldialdehyde (OPA) colorimetric assay (OPA-C), which responds to both free AA and peptides, with an OPA fluorimetric assay (OPA-F), which is insensitive to peptides, to quantify rates of ruminal protein degradation in the inhibitor in vitro system using Michaelis-Menten saturation kinetics. Four protein concentrates (expeller-extracted soybean meal, ESBM; 2 solvent-extracted soybean meals, SSBM1 and SSBM2; and casein) were incubated in a ruminal in vitro system treated with hydrazine and chloramphenicol to inhibit microbial uptake of protein degradation products. Proteins were weighed to give a range of N concentrations (from 0.15 to 3mg of N/mL of inoculum) and incubated with 10mL of ruminal inoculum and 5mL of buffer; fermentations were stopped after 2h by adding trichloroacetic acid (TCA). Proteins were analyzed for buffer-soluble N and buffer extracts were treated with TCA to determine N degraded at t=0 (FD0). The TCA supernatants were analyzed for ammonia (phenol-hypochlorite assay), total AA (TAA; OPA-F), and TAA plus oligopeptides (OPA-C) by flow injection analysis. Velocity of protein degradation was computed from extent of release of 1) ammonia plus free TAA or 2) ammonia plus free TAA and peptides. Rate of degradation (kd) was quantified using nonlinear regression of the integrated Michaelis-Menten equation. The parameters Km (Michaelis constant) and kd (Vmax/Km), where Vmax=maximum velocity, were estimated directly; kd values were adjusted (Akd) for the fraction FD0 using the equation Akd=kd − FD0/2. The OPA-C assay yielded faster degradation rates due to the contribution of peptides to the fraction degraded (overall mean=0.280/h by OPA-C and 0.219/h by OPA-F). Degradation rates for SSBM samples (0.231/h and 0.181/h) and ESBM (0.086/h) obtained by the OPA-C assay were more rapid than rates reported by the National Research Council (NRC). Both assays indicated that the 2 SSBM differed in rumen-undegradable protein (RUP) content; the more slowly degraded SSBM had RUP content (35% by OPA-C) similar to that reported by the NRC. The RUP content of ESBM (42% by OPA-C) was lower than the NRC value. Preliminary studies with 4 additional protein concentrates confirmed that accounting for peptide formation increased degradation rate; however, a trend for an interaction between assay and protein source suggested that peptide release made a smaller contribution to rate for more slowly degraded proteins. The OPA-C assay is a simple and reliable method to quantify formation of small peptides.