The effects of roasting temperature applied to whole soybeans on site of digestion by steers: II. Protein and amino acid digestion

A 4 x 5 Youden square design was used to determine the effect of roasting temperature of whole soybeans on escape of CP from the rumen and disappearance of N from the small intestine in steers. Four steers (average BW 373 kg +/- 30.7) cannulated at the rumen, duodenum, and ileum were fed each of five diets (1.8% of BW) over five periods. The basal diet contained corn silage (50% of diet DM), alfalfa hay (24%), corn-urea premix (6%), corn starch grits (16.6%), and soybean oil (3.4%). Soybeans (16% of diet DM), either raw or heated to an exit temperature of 141, 149, or 157 degrees C in a commercial roaster, replaced the soybean oil and most of the corn starch grits in the soybean-containing diets. Ruminal ammonia N was lower (P < .05) for the basal diet than for the soybean-containing diets. Roasting temperature of whole soybeans had no significant impact on ruminal ammonia N. Total N reaching the duodenum was greater (P < .05) for steers fed the soybean diets than for steers fed the basal diet. Non-bacterial N (dietary N) at the duodenum was increased (P < .05) by feeding soybeans. Soybean N reaching the duodenum decreased with increased roasting temperature. Increased roasting temperature of whole soybeans seemed to make the soybeans more brittle, subsequently increasing degradation of CP in the rumen. However, disappearance of soybean N in the small intestine, as a proportion of the soybean N entering the small intestine, increased with increased roasting temperature. Apparent total tract N digestibility was increased (P < .05) by feeding soybeans. Flow to the duodenum and small intestinal digestibility of total, essential, and nonessential amino acids increased (P < .05) when soybeans were fed and when roasted vs raw soybeans were fed. Under normal roasting conditions, it seemed that little potential for heat damage to the soybean protein existed. Instead, undesirable effects of heating on handling characteristics of the soybeans were reached before the point at which loss of nutritive value occurred. Feeding steers diets containing roasted whole soybeans increased the N and amino acids available to steers over steers fed diets containing raw soybeans due to increased ruminal soybean nitrogen escape and increased small intestinal digestibility.     

Effect of temperature of wet extrusion on the nutritional value of full-fat soyabeans for broiler chickens

1. An experiment was conducted to determine the temperature for wet extrusion of full-fat soyabeans (FFS) needed to produce maximum chicken performance. 2. FFS were either unprocessed or extruded at 5 different temperatures (118 degrees, 120 degrees, 122 degrees, 126 degrees and 140 degrees C) in a wet extruder. Diets were prepared with the different FFS, and a diet prepared with soyabean meal (SBM) was included as a control. The 7 experimental diets were fed to individual groups of 40 chickens each, for a period of 35 d. Trypsin inhibitor activity (TIA), urease activity (UA), and protein solubility in potassium hydroxide (PS) were measured in all FFS and in the SBM. 3. Diets prepared with raw FFS and FFS extruded at 118 degrees and 120 degrees C resulted in significantly lower body weights and in pancreatic hypertrophy; maximum growth rate was obtained with FFS extruded at 122 degrees and 126 degrees C, while minimum pancreas weight was seen in chickens fed FFS extruded at 140 degrees C. 4. Although TIA, UA, and PS all decreased with increasing temperature of extrusion, TIA provided the best prediction of the feeding value of soyabeans for chickens.     

Nitrogen utilization in pigs fed diets with soybean and rapeseed products leading to different ileal endogenous nitrogen losses

Nitrogen (N) balance was determined in 36 pigs (BW 24 to 30 kg) fed diets inducing different ileal endogenous N losses (ENL). We tested the hypothesis that enhanced ENL may be indicative of a higher recycling of endogenous proteins that will induce a greater urinary N loss and a lower efficiency of the dietary N utilization for retention. The cornstarch-based diets contained either soy concentrate (SC), soybean meal (SBM), a mixture of toasted and untoasted soybean meal (mSBM), dehulled-toasted rapeseed cake (RC1), non-dehulled-toasted rapeseed cake (RC2), or dehulled-untoasted rapeseed cake (RC3). The diets were balanced for their content of apparent ileal digestible (ID) CP (108 g/kg feed) and apparent ID of Lys, Thr, Met+Cys, Trp, and Ile. Feeding level was 2.7 times ME for maintenance per kilogram BWx75 and restricted to 88% of the requirements for ID Lys as the first-limiting amino acid. During a 5-d period, urine and feces were collected daily in metabolism cages. Compared with the SC diet (low ENL), the diets with SBM (medium ENL) and mSBM (high ENL) resulted in a greater (P < .05) urinary N excretion. Nitrogen retention tended to be less (P = .08) in pigs fed diets that caused greater ENL. The utilization of ID N for retention in pigs fed the mSBM diet was lower (P < .05) than for those fed the SC diet. There were no differences in urinary N excretion, N retention, and the utilization of ID N for retention in pigs fed the rapeseed diets of different fiber contents (hulls as the NDF source). We concluded that, at similar intakes of the first-limiting ID amino acid, N retention in pigs fed soybeans tended to be reduced by greater ENL as induced by antinutritional factors (e.g., trypsin inhibitors). Rapeseed hulls, as the predominant fiber source, do not affect N retention and the utilization of ID N for retention.     

Failure of soybean trypsin inhibitor to exert deleterious effects in calves

To evaluate nutritional effects induced in calves by feeding soybean trypsin inhibitor, 16 calves were fed 1) raw soybeans, 2) heated soybeans, 3) heated soybeans plus soybean trypsin inhibitor, 4) heated (raw soybeans plus soybean trypsin inhibitor). Ration 1 caused depression of growth and reduced digestibility of protein and fat as compared to Ration 2. No differences were significant in calves fed Rations 3 and 4. The weights and enzymatic activities of pancreas were similar in all groups. Soybean trypsin inhibitor plays a minor role, if any, in calf nutrition.     

Bioavailability of the digestible lysine and total sulfur amino acids in meat and bone meals varying in protein quality

The digestibility and bioavailability of amino acids (AA) in meat and bone meals (MBM) may vary greatly due to different processing conditions. In the present study, two experiments were conducted to evaluate formulation of diets containing high or low quality MBM on a total AA basis vs a digestible or bioavailable AA basis compared to a corn-soybean meal control diet. Lysine, methionine, and cystine digestibilities (precision-fed cecectomized rooster assay) were 92, 91, and 71%, respectively, for high quality MBM and were 71, 83, and 31%, respectively, for the low quality MBM. Bioavailability values (slope-ratio chick growth assay) for TSAA in the two MBM were approximately 15 percentage units lower than the digestibility values. Male crossbred chicks were fed a 20% CP corn-SBM diet or corn-SBM diets containing 10 or 20% high or low quality MBM that were formulated to be equal in total, digestible, or bioavailable AA to the corn-SBM diet. All diets contained 3,200 kcal of TMEn/kg, 1.4% Ca, and 0.7% nonphytate P and were fed to chicks from 8 to 22 d posthatching. Growth performance of chicks fed 10 or 20% high or low quality MBM on a total AA basis was lower (P < 0.05) than that of chicks fed the corn-SBM diet. Growth of chicks fed 10% low quality MBM or 10 or 20% high quality MBM on a digestible or bioavailable basis was equivalent to that of chicks fed the corn-SBM diet; however, dietary inclusion of 20% low quality MBM depressed growth (P < 0.05) even on a digestible or bioavailable AA basis. Further supplementation of the latter diet with additional AA yielded growth that was similar to the corn-SBM control diet. The results indicated that formulation of diets containing MBM on a digestible or bioavailable AA basis is superior to formulation on a total AA basis. However, feeding high levels of a low quality MBM may require additional AA supplementation to obtain maximum chick growth.     

Site of digestion and milk production by cows fed fats differing in saturation, esterification, and chain length

Four cannulated cows in a 4 x 4 Latin square design were used to study the effects of supplemental dietary fatty acids from roasted soybeans combined with tallow or partially hydrogenated fats, varying in esterification and fatty acid chain length, on nutrient digestion and lactation performance. Diets were formulated to contain (DM basis) 48% forage in addition to 1.5% fatty acids from roasted soybeans and 2.5% fatty acids from tallow, partially hydrogenated tallow triglycerides, partially hydrogenated tallow fatty acids, or a blend of 30% tallow and 70% hydrogenated fatty acids that were rich in palmitic acid. Apparent total tract digestibilities of OM, N, and NDF were similar among diets. Supplemental fat as fatty acids, compared with triglycerides, increased digestibilities of total fatty acids and C18:1 in the small intestine, perhaps indicating that lipolysis was rate-limiting. Fatty acids also increased milk fat percentage and efficiency of 4% FCM production. Although intake of C16 fatty acids was higher for cows fed the fat rich in palmitic acid than for those fed the tallow fatty acids, total duodenal flows of C16 fatty acids were similar, and digestibility in the small intestine was unaffected. Dry matter intake, 4% FCM production, and milk protein percentage were similar among treatments.     

Effects of supplemental protein source on intraruminal fermentation, protein degradation, and amino acid absorption

Cannulated steers were used to determine the effects of supplemental soybean meal, heated soybean meal, fish meal, and a combination of fish meal, heated soybean meal, and corn gluten meal on intraruminal protein degradation and absorption of AA from the small intestine. Organic matter digestion in the reticulo-rumen was greater in steers fed diets supplemented with soybean meal, but whole tract digestibility was not affected by protein source. Total and bacterial CP flows to the abomasum were lower in steers fed diets supplemented with fish meal than in steers fed diets supplemented with heated soybean meal or the combination supplement. Dietary CP flow was 33.5% higher in steers fed diets supplemented with heated soybean meal than in steers fed diets supplemented with soybean meal, fish meal, or the combination supplement. Less essential and nonessential AA flowed to the abomasum and were absorbed from the small intestine of steers receiving diets supplemented with soybean meal. Digestibility of small intestine AA was 21.9% lower in steers receiving the soybean meal treatment. Abomasal flows of Met and Thr and absorption of Lys, Met, and Thr were increased in steers fed diets containing heated soybean meal, fish meal, and the combination supplement. These results suggest that the supply of AA deficient in microbial CP (Lys, Met, and Thr) can be increased and that absorbed AA balance can be changed markedly by selection of rumen escape protein supplements.     

Influence of soybean oil in high fiber diets fed to nonlactating cows on ruminal unsaturated fatty acids and nutrient digestibility

An experiment with a 5 x 5 Latin square design was conducted to determine the effects of the addition of soybean oil to high fiber diets on ruminal fermentation and ruminal lipid concentrations. Diets were 50% bermudagrass hay and 50% concentrate. Soybean oil was added to diets at 0, 2, 4, 6, or 8% of the dietary dry matter (DM). Ruminal samples were collected every 2 h on the last day of each period and analyzed for volatile fatty acids and lipids. The addition of soybean oil decreased DM and organic matter intake but increased fatty acid intake. Soybean oil had no effect on total tract digestibility of DM, organic matter, N, or neutral detergent fiber but decreased digestibility of fatty acids. The addition of soybean oil decreased total volatile fatty acid concentrations and the acetate to propionate ratio. Ruminal concentrations of unsaturated free fatty acids increased nonlinearly as soybean oil in the diets increased but remained < 0.67 mg/g of DM or 3% of the total fatty acids. Ruminal concentrations of total fatty acids and total saturated fatty acids increased nonlinearly as soybean oil in the diets increased. Total unsaturated fatty acid concentrations increased linearly as soybean oil increased. Neutral lipid concentrations in the rumen did not respond to increased soybean oil. These data indicate that large amounts of soybean oil can be fed in high fiber diets without greatly increasing the concentration of ruminal unsaturated fatty acids or depressing nutrient digestibility.     

Preservation of hatchery waste by lactic acid fermentation. 2. Large-scale fermentation and feeding trial to evaluate feeding value

Two waste streams from a Leghorn hatchery were preserved and recycled by fermentation with a by-product carbohydrate and extrusion processing into new feed ingredients that were evaluated with broiler chickens. Cockerel chicks (CC) and a 60:40 ratio of CC:shell waste (CC:SW) were fermented in 189-L barrels for 21 d following grinding, then mixing with a liquid culture (0.2%) and carbohydrate source at 15 and 16.66%, respectively. At 2 wk, pH was 4.44 and 5.09 for the CC and CC:SW products compared with higher values of 6.54 and 6.98 for the raw ingredients at the onset. Negligible hydrogen sulfide and no ammonia gas were recorded during the fermentation period. At 21 d, the fermented CC and CC:SW were extruded, dried, and ground to meals containing CP and TMEn levels of 47.4%, 3,187 kcal/kg, and 33.1%, 2,696 kcal/kg, respectively. Broiler chickens were fed a control diet and the CC (5 and 10%) and CC:SW (2.5 and 5%) ingredient diets with corn and soybean meal for 6 wk to evaluate feeding value and carcass yield. Body weight, gain and feed conversion at 42 d for birds fed diets supplemented with CC or CC:SW at all levels were comparable to those of the control. Diets supplemented with hatchery by-product had no negative effect on carcass measurements except ready to cook carcass and wing yield, which were significantly greater for the 10% CC:SW birds than for the control. These data indicate that nutrient dense hatchery by-products can be preserved with fermentation up to 21 d and support broiler live performance and carcass yield as dietary ingredients equal to or better than a corn-soybean meal control.     

Free amino acid supplementation to steers: effects on ruminal fermentation and performance

Three studies were conducted to evaluate amino acid utilization by cattle. In Exp. 1, five steers (580 kg) were fed 86% rolled corn diets with mixtures of amino acids containing up to 6 g/d DL-Met, 24 g/d L-Lys, 6 g/d L-Thr, and 3 g/d L-Trp. Treatments had little effect on ruminal fermentation, diet digestibility, N flow to the duodenum, or microbial efficiency. Ruminal concentrations of Met and Lys increased linearly (P < .05) with amino acid supplementation, whereas Thr responded quadratically, and Trp was not altered. In Exp. 2, four steers (414 kg) were used to measure effects of dietary monensin or laidlomycin propionate in high-grain diets supplemented with amino acids. Ionophores had no significant effect on ruminal fermentation or outflows of amino acids from the rumen. In Exp. 3, 100 steers (287 kg initial BW) were fed diets containing 1% of a nonprotein N source. Treatments were 1) no supplemental N (UREA), 2) UREA plus soybean meal (SBM), 3) UREA plus 2 g/d DL-Met, 8 g/d L-Lys, 2 g/d L-Thr, and 1 g/d L-Trp, or 4) UREA plus 4 g/d DL-Met, 16 g/d L-Lys, 4 g/d L-Thr, and 2 g/d L-Trp. During the growing period (diets based on whole-plant milo silage), gains were higher for SBM-supplemented steers than for UREA steers and intermediate for steers supplemented with amino acids. Few significant differences in performance were observed among treatments during the finishing phase (diets based on dry-rolled corn) or for the entire experiment, but cattle fed SBM or amino acids tended to be fatter and have better marbling scores and quality grades. Amino acids did not greatly alter ruminal fermentation or cattle performance.     

Nutritional utilization by rats of chickpea (Cicer arietinum) meal and its isolated globulin proteins is poorer than that of defatted soybean or lactalbumin

The effects on performance, digestibility, N utilization and plasma amino acid concentrations of dietary chickpea (Cicer arietinum, var. Kabuli) seed meal, globulin proteins or buffer-insoluble residue [starch + non-starch polysaccharides (NSP) + lignin] were studied in growing rats. Chickpea meal, defatted soybean meal, chickpea globulins and lactalbumin were each incorporated into diets as the sole source of dietary protein (100 g/kg). In addition, chickpea insoluble residue was included in a control diet in the same proportion found in the chickpea meal. Rats were killed while under halothane anesthesia after 10 d of consuming the diets, and ileal contents were washed out and freeze-dried for digestibility measurements. Weight gains and gain:feed ratios of rats fed chickpea diets for 10 d did not differ from those of rats fed defatted soybean but were significantly lower than those of rats given the control (lactalbumin) diet. However, ileal and fecal N digestibilities and N retention by rats fed the chickpea diet were significantly lower than those obtained with the lactalbumin or soybean diet. The inclusion of both chickpea meal or its globulin proteins in the diet significantly increased the amount of N excreted, primarily as urea, through the urine. However, although ileal N digestibility values for chickpea meal were significantly lower, those for its constituent globulins did not differ from control values. Urea levels in plasma in rats fed diets containing chickpea meal, globulins or soybean meal were significantly higher than in those fed lactalbumin. Furthermore, the concentrations of glycine, phenylalanine, histidine, arginine and ornithine in the plasma of rats fed chickpea meal, its globulins or defatted soybean were significantly higher, whereas those of threonine, leucine, lysine and tryptophan were significantly lower than lactalbumin-fed controls. The chickpea insoluble residue had no adverse effects on performance or N utilization by rats. We conclude that the low nutritional value of chickpea meal is likely to be due mainly to adverse effects of its globulin proteins on growth and N metabolism rather than to the action of any known antinutritional factor present in the diet.     

Fungus-fermented soybeans benefit the life cycle of Japanese quail (Coturnix coturnix japonica)

Feeding quail chicks diets containing soybeans fermented with two cultures of Aspergilli (A. oryzae N.R.R.L. 451 and A. oryzae N.R.R.L. 506) resulted in significantly superior weight gains (p less than 0.05) through a 4-week growth period and confirmed previous observations made with identical cultures in broiler studies. Subsequent hen-day egg production and egg size were changed little by diets containing fermented soybeans. The numerical increases in fertility and hatchability were not significant. Progeny also responded to the fermented soybean diets, some carry-over effects were evident.     

Roasted soybeans, blood meal, and tallow as sources of fat and ruminally undegradable protein in the diets of lactating cows

The effect of roasted soybeans, blood meal, and tallow as sources of fat and RUP for lactating dairy cows was studied. Forty-five cows, blocked by age, calving date, and milk yield during the previous lactation, were assigned randomly to the following treatments (ingredient in the DM, RUP as a percentage of CP, and fat in the DM, respectively): 1) soybean meal (16, 35, and 3.2%), 2) whole roasted soybeans (18, 40, and 6.2%), 3) ground roasted soybeans (18, 40, and 6.2%), 4) blood meal (2.7, 40, and 3.2%), and 5) blood meal plus tallow (2.7 and 3, 40, and 6.2%). Diets were fed from wk 3 to 18 of lactation and consisted of 20% alfalfa silage, 30% corn silage, and 50% concentrate. The DMI of blood meal and whole roasted soybean diets was about 11% lower than DMI of the soybean meal diet. Milk yield (38.4 kg/d) and milk fat percentage (3.37%) were similar among diets. The roasted soybean diets resulted in the lowest milk protein percentage. Less than 2.7% blood meal might be advisable for diets fed to high yielding dairy cows to avoid reduced DMI.     

Apparent ileal digestibilities of amino acids in newly weaned pigs fed diets with protease-treated soybean meal

Apparent ileal digestibilities of amino acids were determined in pigs fed cornstarch-based diets with untreated or protease-treated soybean meal as the protein source. Sixteen pigs were fitted with a modified post valve T-cecum cannula on d 14, 15, and 16 after birth and then returned to their sows until d 20 when they were weaned. Twelve of the pigs were selected for the study, which was conducted according to a two-period balanced change-over design. Treatments consisted of soybean meal that was 1) untreated (SBM), 2) processed by incubation (1:2 wt/vol distilled water adjusted to pH 4.5, for 16 h at 50 degrees C; CI-SBM), 3) sprayed with protease (supplied at 1 microL/g of soybean meal; PS-SBM), and 4) processed by incubation, as for CI-SBM, with protease in the water at the rate of 1 microL/g of soybean meal (PI-SBM). Each period consisted of 5 d of adaptation to diets followed by three 8-h collection periods (total of 24 h) that alternated with 8-h periods in which digesta were not collected. Apparent CP digestibilities were similar (P > .05) at 70.4, 72.4, 65.2, and 70.3% for the SBM, CI-SBM, PS-SBM, and PI-SBM diets, respectively. Corresponding amino acid digestibilities were also similar (P > .05), ranging from 62.5, 67.5, 57.9, and 65.0% for alanine to 83.5, 83.4, 78.7, and 84.7% for arginine. Apparent digestibilities were less (P < .05) for Period 1 (on d 7 after weaning) than for Period 2 (on d 16 after weaning). In conclusion, protease treatment of soybean meal had no effect on ileal digestibilities of CP and amino acids in newly weaned pigs.     

Effect of acute heat stress on amino acid digestibility in laying hens

An experiment was conducted to determine the effect of acute heat stress exposure on amino acid digestibility in laying hens. A total of 30 commercial laying hens were singly housed in an environmentally controlled facility, fed a standard laying ration, and exposed to a constant thermoneutral temperature (21 C) for 12 d. The hens were then randomly fed one of three diets (10 hens per diet) and exposed to three consecutive temperature periods (8 d each), which consisted of: 1) a constant 21 C temperature, 2) a cycling temperature of 35 C for 12 h and 29 C for 12 h, and 3) a constant 21 C temperature. The three isonitrogenous (18% CP) diets fed were: 1) a corn-soybean meal diet, 2) a corn-soybean meal diet containing 15% meat and bone meal, and 3) a corn-soybean meal diet containing 5% alfalfa meal and 20% wheat bran. Excreta were collected from all hens during the last 4 d of each temperature period and apparent amino acid digestibility was determined. There was a significant diet effect (P < 0.05) on amino acid digestibility. Digestibility of amino acids in Diet 2 (corn-soybean meal/meat and bone meal) was higher (P < 0.05) than in the other two diets. In addition, digestibility of amino acids in Diet 3 (corn-soybean meal/alfalfa meal/wheat bran) was significantly lower (P < 0.05) than in Diets 1 or 2. Heat stress generally had no significant effect on amino acid digestibility except for His and Lys digestibility. Histidine digestibility was higher during the heat stress period than during the initial and recovery thermoneutral periods, whereas Lys digestibility was higher during the heat stress period than during the initial thermoneutral period. These results indicated that acute heat stress (8 d) had no adverse effects on dietary amino acid digestibility in laying hens.     

The feeding value of soybeans fed to rats, chickens, catfish and dairy cattle is not altered by genetic incorporation of glyphosate tolerance

Animal feeding studies were conducted with rats, broiler chickens, catfish and dairy cows as part of a safety assessment program for a soybean variety genetically modified to tolerate in-season application of glyphosate. These studies were designed to compare the feeding value (wholesomeness) of two lines of glyphosate-tolerant soybeans (GTS) to the feeding value of the parental cultivar from which they were derived. Processed GTS meal was incorporated into the diets at the same concentrations as used commercially; diary cows were fed 10 g/100 g cracked soybeans in the diet, a level that is on the high end of what is normally fed commercially. In a separate study, laboratory rats were fed 5 and 10 g unprocessed soybean meal 100 g diet. The study durations were 4 wk (rats and dairy cows), 6 wk (broilers) and 10 wk (catfish). Growth, feed conversion (rats, catfish, broilers), fillet composition (catfish), and breast muscle and fat pad weights (broilers) were compared for animals fed the parental and GTS lines. Milk production, milk composition, rumen fermentation and nitrogen digestibility were also compared for dairy cows. In all studies, measured variables were similar for animals fed both GTS lines and the parental line, indicating that the feeding value of the two GTS lines is comparable to that of the parental line. These studies support detailed compositional analysis of the GTS seeds, which showed no meaningful differences between the parental and GTS lines in the concentrations of important nutrients and antinutrients. They also confirmed the results of other studies that demonstrated the safety of the introduced protein, a bacterial 5-enolpyruvyl-shikimate-3-phosphate synthase from Agrobacterium sp. strain CP4.     

Clavicular Auscultation. Preferential clavicular transmission and amplification of aortic valve murmurs

1. A diet based on soybean meal and wheat contained insufficient chloride to support normal growth in chicks. 2. Ammonium chloride and sodium chloride were equally good sources of supplementary chloride for the chick. 3. When seven diets providing increasing proportions of chloride from 608 to 1808 mg/kg, were fed to chicks, maximal growth at 21 d was obtained at about 1200 mg chloride/kg diet.     

Effect of betaine on the growth performance of chicks inoculated with mixed cultures of avian Eimeria species and on invasion and development of Eimeria tenella and Eimeria acervulina in vitro and in vivo

At 7 d postinoculation (DPI) with a mixed culture of avian Eimeria species, 21-d-old chicks maintained in batteries and floor pens on a diet containing 0.15% (3 lb/ton) betaine plus 66 ppm (60 g/ton) salinomycin were significantly heavier and had significantly lower feed conversion ratios and mortality than chicks fed diets containing 0.15% betaine or 66 ppm salinomycin alone, or the control diet. At 31 DPI, when the chicks were 45 d old, the differences between the diet groups were not as great as at 7 DPI. In vitro, except at high concentrations, betaine was nontoxic to sporozoites of Eimeria tenella or Eimeria acervulina and had little effect on their invasion and development in cultured cells. In vivo, invasion by E. tenella and E. acervulina sporozoites was significantly reduced in all chicks fed diets containing betaine or salinomycin compared with that in control chicks. There was a significant interaction between betaine and salinomycin that impacted on invasion by both species. Overall development of E. tenella did not appear to be adversely affected by addition of betaine to diets containing salinomycin. Conversely, development of E. acervulina was reduced in chicks fed diets containing 0.075% (1.5 lb/ton) betaine plus 66 ppm salinomycin as compared with that in chicks fed salinomycin alone.     

Effect of raw material source, processing systems, and processing temperatures on amino acid digestibility of meat and bone meals

Experiments were conducted to evaluate amino acid digestibility of 32 commercial meat and bone meals (MBM) varying in raw material source and produced in seven different commercial cooking systems and at two processing temperatures (low vs high) that differed by 15 to 20 C. Raw material sources included all beef, all pork, mixed species, and high bone MBM. True digestibilities of amino acids were determined using the precision-fed cecectomized rooster assay. Protein efficiency ratio (PER) of six MBM varying greatly in amino acid digestibility was determined with chicks fed 10% CP diets containing a MBM as the sole source of dietary protein. The 32 MBM samples averaged 53.2% CP, 2.73% Lys, 0.6% Cys, and 0.75% Met on a DM basis. True digestibility averaged 82% for Lys, 87% for Met, and 47% for Cys. True digestibilities of amino acids varied substantially among processing systems and temperatures, particularly for Lys and Cys. For example, Lys and Cys digestibility ranged from 68 to 92% and from 20 to 71%, respectively, among different MBM. The higher processing temperature generally yielded lower amino acid digestibility than did the low processing temperature. A smaller, less consistent, effect was observed for raw material source. The PER values of the six selected MBM varied from 0.97 to 2.68 and were highly correlated with amino acid digestibility. These results indicated that very high amino acid digestibility MBM can be produced in commercial rendering systems. However, differences in processing systems and temperatures can cause substantial variability in amino acid digestibilities.     

Evaluation of the digestibility of nutrients in pigs by ileal cannulation technique

A simple T-cannula was surgically inserted into the ileum of growing female Large White x Dutch Landrace swine. Chymus samples collected with the help of the cannula were analysed to determine the apparent digestibility of different dietary nutrients such as dry matter, crude protein and starch, as well as of some essential amino acids. The following three experiments were conducted: (I) of the cereals, the "Tewo" triticale variety fed alone and in 1:1 concentrate mixtures with wheat or maize was studied; (II) waxy maize hybrids and maize hybrids of normal endosperm were compared without treatment and after treatment by the Bocchi technology; (III) untreated and extruded maize supplemented either with extracted soybean or with extracted sunflower was also tested. The ileal digestibility of protein, amino acids and starch was determined and compared with values obtained by conventional (faecal) analysis. When feeding triticale alone or in combination with wheat or maize, the ileal digestibility of crude protein and amino acids increased as a result of feeding the cereal combinations (e.g. crude protein 72-79%, lysine 75-79%, threonine 63-78%, methionine 74-86%). Comparison of the two maize hybrids revealed that, with the exception of methionine, lysine and tyrosine, the amino acids of the waxy hybrid had higher ileal digestibility. Treatment of the normal hybrid by the Bocchi technology caused a significant improvement in the ileal digestibility of cystine, isoleucine, lysine, valine, and dry matter. This treatment also improved the faecal digestibility of all test nutrients but methionine. Bocchi treatment of the waxy hybrid significantly improved the ileal digestibility of isoleucine, leucine, methionine, tyrosine and valine, and the faecal digestibility of cystine, dry matter, and crude protein. No major variety- or treatment-related differences were found in the digestibility of starch. As a result of extrusion, the digestibility of nutrients of the soybean + maize mixture increased from 61.6% to 70.3% (crude protein), from 41.1% to 59.4% (threonine), from 60.1 to 72.0% (methionine), and from 70.7% to 82.7% (lysine). The same treatment of the sunflower + maize mixture increased the digestibility of crude protein from 80.6% to 84.5%, that of threonine from 78.1% to 80.6%, that of methionine from 79.7% to 84.3%, while that of lysine from 61.4% to 72.3%. The ileal digestibility of starch was 97-98% for both mixtures. As a result of extrusion, most of the faecal digestibility values showed a significant improvement for both the soybean- and the sunflower-containing mixtures. The favourable effect exerted by extrusion on the digestibility of nutrients is markedly influenced by the feed components.