Raw Soybean Diet Research Articles

Soybean Trypsin Inhibitor(s) Reduce Absorption of Exogenous and Increase Loss of Endogenous Protein in Miniature Pigs

It was the purpose of this study to define whether trypsin inhibitors impair protein digestibility via enhanced loss of exogenous or endogenous protein by quantifying those losses using the homoarginine technique, recently developed in this laboratory. Pigs fitted with permanent ileal T-cannulas were fed test meals containing homoarginine-labeled protein. The meals contained casein and increasing doses of trypsin inhibitors (Experiment 1) or alternatively either heat-treated or raw ground soybeans (Experiment 2). Following a casein meal (425 mmol nitrogen, no trypsin inhibitors), ileal protein was predominantly of endogenous rather than of exogenous origin (105 vs. 9 mmol nitrogen). Addition of isolated trypsin inhibitors (3000 mg) enhanced appearance of both endogenous and exogenous protein at the ileum (by 73 and 9 mmol nitrogen, respectively). Feeding raw instead of heat-treated soybeans in one single test meal caused a significant increase of endogenous protein from 217 +/- 42 to 263 +/- 47 mmol (mean +/- SEM) and of exogenous protein from 16 +/- 3 to 48 +/- 14 mmol. If fed continuously for 1 wk, a raw soybean diet caused endogenous protein loss to rise significantly from 221 +/- 26 to 432 +/- 85 mmol. We conclude that ingestion of food containing trypsin inhibitor affects nitrogen balance more by losses of amino acids of endogenous secreta than by losses of dietary amino acids.

Use of protected fat sources to reduce fatty acid biohydrogenation and improve abomasal flow in dry dairy cows

The objective of this study was to evaluate the effects of dietary fat supplementation on dry dairy cows feed intake, digestion, ruminal kinetics, biohydrogenation, and abomasal flow of fatty acids (FAs). Eight Holstein rumen and abomasum fistulated dry cows (average body weight of 614±59kg), were assigned to a replicated 4×4 Latin square design experiment, with 21-d periods. The experimental diets were: 1) control (CON): corn- and soybean meal-based diet, with no fat source; 2) soybean oil (SO) diet with 30g/kg dry matter (DM) of soybean oil; 3) whole raw soybean (WS) diet with 160g/kg DM of whole raw soybean grain; 4) calcium salts of fatty acids (CS) diet with 32g/kg DM of calcium salts of unsaturated FA. Fat-supplemented diets increased ether extract intake and digestibility without affecting DM intake. However, these diets promoted a decrease in DM and neutral-detergent fiber (NDF) total tract apparent digestibility. Fat sources decreased ruminal acetate to propionate ratio (C2:C3). In addition, SO diet increased ruminal propionate concentration and decreased C2:C3 in relation to protected sources of FA (CS and WS). Furthermore, cows fed CS diet exhibited higher ruminal pH, NH3-N and acetate concentration compared to those fed WS diet. Fatty acid supplementation did not alter serum glucose and urea concentration, but increased the serum cholesterol concentration. Although FA supplementation increased net energy intake of cows, energy and nitrogen balances, and microbial protein synthesis were not affected by the experimental diets. Fat supplementation had no effect on ruminal digestion neither on DM and NDF passage rates. Cows fed CS and WS diets presented higher DM and NDF ruminal digestion rates whether compared to SO one. Consequently, cows fed CS and WS had higher truly digestible NDF ruminal removal rate than those fed SO. Calcium salts of unsaturated FA increased DM and NDF rumen passage rate and decreased NDF digestibility in relation to WS diet. Fat-supplemented diets increased the abomasal flows of C18:2, trans C18:1, C18:0, C16:0 and total FA. The CS supplementation resulted in a higher abomasal flow of DM, total FA, trans C18:1, C16:0 and C18:3 when compared to WS one. On the one hand, FA supplementation increased C18:2 and C18:1 biohydrogenation rates; on the other hand, it protected FA sources decreased C18:2 and C18:1 biohydrogenation rates. In conclusion, fat-protected sources were effective to prevent FA from ruminal biohydrogenation.

Nutritive Evaluation of Lysine- and Methionine-Supplemented Raw Vs Heat-Processed Soybean to Replace Fishmeal as a Dietary Protein Source for Grey Mullet, Mugil cephalus, and Milkfish, Chanos chanos

Two experiments were conducted to study the effect of methionine- and lysine-supplemented raw and hydrothermically processed full-fat soybean as a dietary protein source on growth performance, digestibility, and digestive enzyme activity in grey mullet, Mugil cephalus (mean BW 0.55 g), and milkfish, Chanos chanos (mean BW 3.83 g). Eight isocaloric (gross energy about 18.27 kj g−1) and isonitrogenous (crude protein about 40%) diets (1–4 = raw soybean based; 5–8 = processed full-fat soybean based) were formulated. A fishmeal-based diet was used as the reference/control diet. Growth performance, nutrient retention, feed conversion ratio (FCR), and protein digestibility in fishes correlated well with the trypsin inhibitor activity levels of the diets. Carcass phosphorous levels were significantly (P < 0.05) higher in fish fed the fishmeal control diet. Irrespective of the fish species, significantly (P < 0.05) lower levels of total ammonia excretion and reactive phosphate production (mg kg−1 BW d−1) were recorded where the fish were fed processed full-fat soybean diets compared with the fish fed fishmeal or raw soybean diets. Among these diets, the best growth performance and the lowest levels of metabolic waste were obtained in fishes fed the methionine- and lysine-supplemented processed soybean-based diets containing no fishmeal.

The Effect of Raw Soybean on Oxidative Status of Digestive Organs in Mice

The present study was undertaken to specify the effect of raw soybean on oxidative status of digestive organs in mice. For this purpose, thirty male (C57BL/6J) mice were randomly divided into three groups and fed on different diets as follows: Group 1 was fed on control diet, Group 2 was fed on raw soybean diet and Group 3 was fed on raw soybean diet supplemented with 30 mg/kg cysteamine. After two weeks of feeding, duodenum, liver and pancreas samples were collected to measure oxidative and antioxidative parameters. The results show that ingestion of raw soybean markedly increased contents of superoxide anion and malondialdehyde (MDA) and activity of inducible nitric oxide synthase (iNOS), decreased activity of superoxide dismutase (SOD), T-AOC and content of reduced glutathione (GSH) in digestive organs of mice (P < 0.05). In the group fed with raw soybean diet supplemented with cysteamine, oxidative stress was mitigated. However, oxidative parameter levels were still higher than those of control diet-fed group. The present study indicates that ingestion of raw soybean could result in an imbalance between oxidant and antioxidant, and thus induce oxidative stress in digestive organs of mice.

COMPARISON OF GROUND RAW SOYBEAN AND SOYBEAN MEAL DIETS ON CARCASS TRAITS OF GILTS

ABSTRACT As part of an ongoing reproductive efficiency study with gilts fed a raw soybean (RSB) diet, an assessment of carcass traits was performed to measure the effect of antinutritional factors present in RSB. Yorkshire × Landrace crossbred gilts (n = 20) were assigned to balanced isonitrogenous (crude protein 14%), isocaloric diets using either soybean meal (SBM, n = 10) or ground RSB (n = 10) as the protein supplement. Gilts were fed to day 35–45 of gestation and then harvested for recovery of the reproductive tract and carcass assessment. Carcass trait values included: a decrease (P ≤ 0.05) in hot carcass weight of RSB gilts, but no differences in carcass length, back fat thickness (cm) at 1st rib, 10th rib, last rib, last lumbar and average back fat. Loin area cm2, % fat free lean, muscle score and United States Department of Agriculture grade scores did not differ (P &gt; 0.05). Thus, supplementing diets of prepubertal gilts through to early gestation with ground RSB had no observed adverse effects on carcass quality traits.PRACTICAL APPLICATIONSRaw soybeans (RSB) are not commonly used in swine diets due to known presence of antinutritional factors that may retard growth in young swine and may also affect carcass quality. However, the effect of using RSB on carcass quality in older swine has yet to be examined. The data from this study show that supplementation of swine diets with RSB can be used in gilts 155 days of age and older without affecting carcass quality.

Effects of raw soy diet on the rat parotid gland

Soy is increasingly used as a food additive. In women, it is recommended as an alternative to hormonal replacement therapy and/or a preventive agent against breast cancer and osteoporosis. Previous data revealed that rats fed on raw soybean diet developed pancreas hypertrophy and hyperplasia. An animal model was used in our experiment to examine the effects of raw soybean on parotid gland of rats. The purpose of this study was to light on the role of different neuropeptide-containing nerve fibres on changes in the acinar cells. The morphological structure and the neuropeptide-containing nerve fibers (NPY, GAL, SOM, SP, CGRP, VIP) of the glands were examined by light and electronmicroscopy. Significant increase of the organ weight was detected in the animals fed by raw soybean compared to control samples. Changes in the number of different neuropeptide-containing nerve fibres were various: Significant decrease in the NPY-immunoreactive (IR) and significant increase in the GAL-IR nerve fibres were observed....

The effects of dry extrusion temperature of whole soybeans on digestion of protein and amino acids by steers1

Five Holstein steers (450 kg) with cannulas in the rumen, proximal duodenum, and terminal ileum were used in a 5 × 5 Latin square design to study the effects of extrusion temperature on site of digestion of nitrogenous compounds in whole soybeans. The basal diet contained 50% corn silage, 24% alfalfa hay, 16.6% corn starch, 4.05% ground corn, 1% urea, and 3.4% soybean oil. Raw soybeans or soybeans extruded at 116, 138, or 160°C (diets 116, 138, and 160, respectively) replaced the soybean oil and most of the corn starch in the test diets. Total N (g/d) reaching the duodenum was 232, 293, 285, 308, and 299 for the basal, raw, 116, 138, and 160 diets, respectively. No differences were observed between the raw and extruded soybeans (P = 0.81), or for the linear or quadratic effects of extrusion temperature (P = 0.56 and P = 0.45, respectively). Nonbacterial N (g/d) reaching the duodenum was 63.1, 104.6, 106.7, 101.9, and 113.9 for the same diets, respectively, and was not influenced by extrusion or extrusion temperature. Nitrogen disappearance from the small intestine (g/d) was 150 for the basal diet, 194 for the raw soybean diet, and 187, 221, and 213 for the 116, 138, and 160°C extruded diets, respectively; no differences were observed between the raw and the extruded soybeans, or for diets containing soybeans extruded at different temperatures. Nitrogen disappearance (% of N entering) from the small intestine was lower (P < 0.05) for steers fed the basal diet than for steers fed the soybean-supplemented diets (64.1 vs 68.5%). No differences (P > 0.10) due to extrusion temperature were detected for flows of individual, essential AA, nonessential AA, and total AA at the duodenum. As extrusion temperatures increased, there were linear increases (P < 0.10) in disappearance (g/d) of all individual AA from the small intestine except for methionine and glycine. Essential, nonessential, and total AA disappearance from the small intestine were increased linearly (P < 0.10) with increasing extrusion temperature. Extrusion of soybeans can protect soy protein against extensive ruminal degradation without compromising intestinal digestibility.

The effects of dry extrusion temperature of whole soybeans on digestion of protein and amino acids by steers.

Five Holstein steers (450 kg) with cannulas in the rumen, proximal duodenum, and terminal ileum were used in a 5 x 5 Latin square design to study the effects of extrusion temperature on site of digestion of nitrogenous compounds in whole soybeans. The basal diet contained 50% corn silage, 24% alfalfa hay, 16.6% corn starch, 4.05% ground corn, 1% urea, and 3.4% soybean oil. Raw soybeans or soybeans extruded at 116, 138, or 160 degrees C (diets 116, 138, and 160, respectively) replaced the soybean oil and most of the corn starch in the test diets. Total N (g/d) reaching the duodenum was 232, 293, 285, 308, and 299 for the basal, raw, 116, 138, and 160 diets, respectively. No differences were observed between the raw and extruded soybeans (P = 0.81), or for the linear or quadratic effects of extrusion temperature (P = 0.56 and P = 0.45, respectively). Nonbacterial N (g/d) reaching the duodenum was 63.1, 104.6, 106.7, 101.9, and 113.9 for the same diets, respectively, and was not influenced by extrusion or extrusion temperature. Nitrogen disappearance from the small intestine (g/d) was 150 for the basal diet, 194 for the raw soybean diet, and 187,221, and 213 for the 116,138, and 160 degrees C extruded diets, respectively; no differences were observed between the raw and the extruded soybeans, or for diets containing soybeans extruded at different temperatures. Nitrogen disappearance (% of N entering) from the small intestine was lower (P < 0.05) for steers fed the basal diet than for steers fed the soybean-supplemented diets (64.1 vs 68.5%). No differences (P > 0.10) due to extrusion temperature were detected for flows of individual, essential AA, nonessential AA, and total AA at the duodenum. As extrusion temperatures increased, there were linear increases (P < 0.10) in disappearance (g/d) of all individual AA from the small intestine except for methionine and glycine. Essential, nonessential, and total AA disappearance from the small intestine were increased linearly (P < 0.10) with increasing extrusion temperature. Extrusion of soybeans can protect soy protein against extensive ruminal degradation without compromising intestinal digestibility.

Raw or Extruded Soybeans and Rumen-Protected Methionine and Lysine in Alfalfa-Based Diets for Dairy Cows

Fifty-seven Holstein cows (19 primiparous) were assigned to one of four dietary treatments arranged as a 2 × 2 factorial during d 22 to 150 of lactation to examine the effects of raw or extruded (149°C) soybeans and of rumen-protected methionine and lysine supplements on lactation performance. Dietary DM contained 16.5% CP and consisted of 32.2% alfalfa silage, 5.4% alfalfa pellets, 10.4% corn silage, 38.5% high moisture shelled corn, 11.4% nitrogenous supplements, and 2.1% minerals and vitamins. From d 15 prepartum to d 21 of lactation, all cows were fed a protein supplement of raw and extruded soybeans in a 1:1 ratio. During the experimental period, an average of 18.9kg of DM were consumed. This contained, for the amino acid-supplemented treatments, 14.2g each of rumen-protected DL-methionine and L-lysine. Experimental data were adjusted by covariance for means measured during d 4 to 21. Dietary treatments did not affect yield of milk, milk protein or milk casein, DMI, BW and condition, or plasma urea N. Extruded soybeans depressed milk fat percentage. Evaluation of diets in continuous culture fermenters indicated no differences in digestibility of DM and carbohydrates. Ammonia N concentration in the effluent and CP degradation were lower for extruded than for raw soybean diets. Flows of NAN and total amino acids from fermenters did not differ among diets.

Value of raw soybeans and soybean oil supplementation in sow gestation and lactation diets: a cooperative study.

A cooperative study using 215 sows during two parities (349 litters) was conducted at six stations to determine the effect of raw soybeans in gestation and lactation diets on sow and litter performance. Sows were bred and allotted to fortified corn diets containing either soybean meal (control) or raw soybeans. A corn-soybean meal-soybean oil diet, isocaloric to the raw soybean diet, was included as a third treatment at three stations. All diets contained 14% CP. These diets were fed during both gestation and lactation through two parities. The daily gestation feed intake ranged from 1.8 to 2.3 kg/sow, depending on station. During lactation, the sows were allowed ad libitum access to their respective diets. Gestational weight gain was not influenced by diet, but sows fed raw soybeans consumed less (P less than .01) feed during lactation and had greater (P less than .01) lactational weight loss and their pigs were lighter in weight (P less than .05) both at 21 d and at weaning (varied between 3 and 5 wk of age). Sows fed the diet with supplemental oil had reproductive and lactational performance similar to those fed the control diet. Milk obtained at d 10 to 14 of lactation from sows fed raw soybeans had lower (P less than .05) protein content than milk from sows fed the other two diets, but fat content of the milk tended to be increased by raw soybeans or by added soybean oil. Return to estrus was not affected by diet.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of germinated and heated soybean meals on plasma cholesterol and triglycerides in rats

Soybean may be useful in diets for the prevention of cardiovascular disease and the treatment of type II hyperlipoproteinemia as it lowers blood cholesterol levels. However, unpleasant organoleptic qualities and the presence of antinutritional substances hinder its use. Some of these problems may be partially solved by germinating the seeds or heating the meals. The effects of the duration of soybean germination and of heating the meal were studied in Wistar rats. Dietary meal composition, plasma cholesterol and triglyceride levels were evaluated after feeding rats with various soybean meal or casein diets containing 10% protein for 6 weeks. Plasma cholesterol and triglyceride levels were 0.81 +/- 0.11 and 0.82 +/- 0.23 g/l respectively after the casein diet and 0.90 +/- 0.10 and 0.51 +/- 0.17 g/l after the raw soybean diet. Soybean germination had a hypercholesterolemic effect (1.05 +/- 0.11 g/l after 5 d). Heating the raw meal or germinated soybean meal did not affect cholesterol levels, though it suppressed the hypotriglyceridemic effect. The triglyceride-lowering effect of soybean was probably caused by the presence of thermolabile substances or by the quantity of food ingested. The unexpected increase in blood cholesterol levels may have been due to the effect of the low dietary protein levels.

Amino acid-supplemented raw soybean diets for finishing swine.

Growth and carcass traits of finishing swine fed amino acid-supplemented raw soybean (RSB) diets were examined. Experiments 1 and 2 were identical and included the following treatments: 1) corn-soybean meal (SBM), 2) corn-RSB (lysine equal to Diet 1), 3) Diet 2 + .15% L-lysine (LYS), 4) Diet 3 + .1% L-threonine (THR), 5) Diet 3 + .05% L-tryptophan (TRP), 6) Diet 3 + .15% DL-methionine (MET) and 7) Diet 3 + THR + TRP + MET equivalent to Diets 4 to 6. The unsupplemented corn-RSB diet reduced (P less than .05) gain, gain:feed, plasma urea N, loin eye area, and percentage of muscling compared with the corn-SBM diet. The addition of LYS or LYS + TRP generally improved these response variables, whereas the addition of LYS + THR or LYS + MET tended to reduce gain and gain:feed compared with the LYS addition alone. The LYS + THR + TRP + MET addition resulted in growth and carcass traits that were intermediate between those of pigs fed the corn-RSB and the corn-SBM diets but not different (P greater than .05) from either. Experiment 3 included Diets 1, 2 and 7 from Exp. 1 and 2, in addition to the following treatment: corn-RSB + LYS + THR + TRP. The LYS + THR + TRP addition improved (P less than .05) growth and carcass traits compared with the LYS + THR + TRP + MET addition.(ABSTRACT TRUNCATED AT 250 WORDS)

A comparison of raw soybeans and soybean oil as energy sources for finishing pigs (1987)

Two hundred and seventy pigs averaging 125 lbs were utilized in two growth trials to determine the effects of raw soybeans or soybean oil on finishing pig performance. In each trial, raw soybeans or soybean oil were substituted for milo to provide 2 or 3% added fat. Pigs fed these diets were compared to pigs fed a milo-soybean meal diet (control). In Experiment 1, raw soybeans or soybean oil were added in place of milo in a 15% crude protein, .7% lysine diet. Increasing levels of raw soybeans resulted in greater trypsin inhibitor content compared to the control or soybean oil diets. Pigs fed diets containing soybean oil showed a slight tendency (P(.15) for improved average daily gain (ADG) compared to pigs fed raw soybeans. Pigs fed raw soybeans also had poorer feed efficiency (F/G) compared to those fed soybean oil (P<.0l) and the control diet (P<.05). Plasma urea concentrations measured on day 21 of the trial were lower for pigs fed the soybean oil diets than for pigs fed the control (P<.10) and raw soybean (P>.0l) diets. In Experiment 2, control pigs were fed a low protein, lysine-fortified diet (11.2% crude protein, .60% lysine). Pigs fed the control diet tended to have higher ADG (P<.12) and average daily feed intake (ADFI) than pigs fed diets containing raw soybeans or ,soybean oil. Feed efficiency was not influenced by dietary treatment. Plasma urea concentrations were highest (P<.0l) for pigs fed diets containing raw soybeans. These results indicate that, in a typical finishing diet (l5% crude protein, .7% lysine), the addition of raw soybeans as an energy source reduced pig performance compared to diets containing 2 or 3% soybean oil. Additions of raw soybeans also resulted in poorer F/G for pigs compared to the diet without added fat. However, when low protein diets were fed, fat additions from either soybean oil or raw soybeans resulted in slightly poorer pig performance compared to the control diet.; Swine Day, Manhattan, KS, November 19, 1987

Short-term (8-day) effects of a raw soybean diet on exocrine pancreatic secretion and plasma gastrointestinal hormone levels in the pig.

The aim of the present study was to investigate the short-term (8-day) effects of feeding a raw soybean diet on exocrine pancreatic secretion and the plasma levels of gastrointestinal hormones in pigs. After adaptation to a heated soybean diet, 6 pigs (36.5 +/- 0.8 kg) were fitted with permanent fistulae of the pancreatic duct, the duodenum and a carotid artery. After post-surgical recovery of 8 days, the animals were submitted to two experimental periods, a 4-day period during which they were fed the heated soybean diet and an 8-day period during which they received the raw soybean diet. Exocrine pancreatic secretion and plasma levels of secretin, cholecystokinin, VIP, PP, somatostatin and gastrin were monitored each day of the two experimental periods. On the first day of raw soybean ingestion and till its end, the daily volume of pancreatic juice was higher than the mean volume measured during heated soybean ingestion. On the contrary, daily total protein output was unchanged. Specific activities of chymotrypsin, amylase and lipase were not modified by the raw soybean diet whereas, from the third day of the experimental period, that of trypsin was higher than the corresponding mean value determined during the first experimental period. Plasma levels of secretin and VIP were higher throughout raw soybean ingestion than the corresponding mean levels determined during the first experimental period. The plasma level of cholecystokinin increased only slightly and in the first days of the second experimental period only. The other gastrointestinal hormones studied were slightly (gastrin) or not (somatostatin, PP) affected by raw soybean feeding. It is suggested that feedback control of exocrine pancreatic secretion in pigs was the mechanism involved in the increase of pancreatic juice observed when raw soybean was fed. This volume increase would result from secretin release into the blood.

Protein Degradation in Rumen and Amino Acid Absorption in Small Intestine of Lactating Dairy Cattle Fed Heat-Treated Whole Soybeans

Four lactating Holstein cows fitted with rumen cannulae and T-type cannulae in proximal duodenum and terminal ileum were used to measure protein degradation in the rumen and amino acid flow and absorption in the small intestine. Soybean meal, whole soybeans, and whole soybeans extruded at 132 and 149°C provided 50% of the protein in diets that contained 51% grain, 36% corn silage, and 13% alfalfa hay (dry matter). Spot samples of digesta were collected from duodenum and ileum during 96h, and lanthanum was an indigestible marker to estimate flow and digestibility of nutrients. With diaminopimelic acid as a microbial marker, apparent degradations of dietary crude protein in the rumen were 73, 80, 66, and 60% for diets containing soybean meal, whole soybeans, and whole soybeans extruded at 132 and 149°C. Because of the extensive degradation of protein with the raw soybean diet, less total amino acids reached the duodenum, and because of decrease of availability, absorption from the small intestine (g/day) was lowest with this diet. Feeding diets containing extruded whole soybeans increased availability of total essential amino acids in the small intestine compared with diets containing soybean meal and whole soybeans. Absorption from the small intestine (g/day and percent entering) of individual amino acids was generally higher for extruded whole soybean diets.

Soybean diet lowers breast tumor incidence in irradiated rats.

This paper examines the relationship between feeding a diet rich in protease inhibitors and the reduction of mammary cancer induced by x-irradiation in Sprague-Dawley rats. Of a total of 145 irradiated animals, 44% of the 45 rats fed a raw soybean diet containing a high concentration of protease inhibitor developed mammary tumors as compared to 74% of 50 rats fed a casein diet containing no protease inhibitor. Animals fed Purina rat chow which contained low levels of protease inhibitor exhibited a 70% mammary tumor incidence. No spontaneous neoplasms were found in any of the non-irradiated animals on the raw soybean diet whereas about 10% of the animals on the protease-free diet developed tumors. Thus, soybeans which are rich in protease inhibitors reduced the induction of mammary cancer in x-irradiated rats. This work suggests that diets rich in protease inhibitors may contribute to reducing cancer incidence in man.

Effect of Dietary Raw Soybean and Soybean Trypsin Inhibitor on Trypsin and Chymotrypsin Activities in the Pancreas and in Small Intestinal Juice of Growing Swine

Sixty-eight growing gilts with a 12 kg average initial weight were used in seven trials to study the effect of dietary raw soybean (Harosov) and SBTI (Kunitz soybean trypsin inhibitor) on pancreatic and small intestinal trypsin and chymotrypsin activities. A solvent-extracted, heated soybean meal (SBM) was used, cause reduced growth. Both a single-meal and continuous feeding of the raw soybean diet caused a decrease in the pancreatic trypsin and chymotrypsin activities. In contrast, to the rat and the chick, the pancreas of the pigs did not enlarge subsequent to consumption of the raw soybean or SBTI diets. Raw soybean feeding also resulted in an inhibition of the intestinal trypsin and chymotrypsin activities. This inhibiting effect was greater than that of the SBTI, especially the chymotrypsin-inhibiting effect. This suggested that soybean constituents other than the SBTI, such as the Bowman-Birk inhibitor, caused inhibition. In the pig the inhibition of the intestinal proteolysis may be a major cause of reduced growth when raw soybean is fed.

Stomach and Upper Intestine of the Rat in the Regulation of Food Intake

The role of the upper intestine in the regulation of food intake and gastric emptying has been studied in normal, gastrectomized, and "crossover" rats, parabiotic rats with a common visceral cavity in which the proximal duodenum of each parabiont is anastomosed to the pylorus of the stomach of the partner. One rat of "crossover" pairs eats and the partner eats little or nothing. Normal rats fed a raw soybean (RS) diet ate less and gastric evacuation proceeded more slowly than in normal rats fed a heated soybean (HS) diet. It is postulated that RS contains a heat-labile intestinal irritant. The upper intestine of gastrectomized rats regulates food intake and prevents overloading of the intestine. Force feeding of excessive amounts of the RS diet elicited the secretion of much more solids and nitrogen into the upper intestine than did similar amounts of the HS diet. The upper intestines of "crossover" rats lose all control over entry of gastric contents into their duodena. Fed ad libitum, the parabiont whose stomach emptied first, ate continuously, while the recipient partner showed diarrhea. It is postulated that the control of food intake traditionally assigned to the stomach resides, rather, in the upper intestine.

Nutritive Value of Salt-bed Roasted Soybeans for Broiler Chicks

A roaster was built which used heated granular salt (NaCl) as the heat transfer medium. Rapid and uniform roasting of soybeans was accomplished using such equipment. A 33 factorial experimental design was used to determine the effect of the roasting variables on soybeans. Chicken feeding trials and soybean protein availability measurements were used for evaluation.The best roasting conditions were 272° C. salt bed, 20 sec. contact of salt and soybean, and 120 sec. holding time. These roasting conditions also reduced the soybean moisture. Chicken rations containing soybeans roasted at these conditions produced 41 percent and three percent higher weight gains than a raw soybean diet and a commercial soybean meal diet, respectively, at the end of fourth week. It was concluded that the salt bed roasted soybeans were excellent for chick growth.

PROCESSING SOYBEANS WITH SODIUM HYDROXIDE AND COPPER SULFATE FOR PIGS

Three feeding trials involving a total of 120 individually fed pigs and a metabolism trial were conducted to evaluate the influence of moist heating of soybeans on performance. In one trial sodium hydroxide and copper sulfate, singly or in combination, were added to the cooking water. In the other two trials copper was added to the vitamin–mineral premix. Pigs fed cooked soybeans or soybean meal performed similarly and their performance was superior to that of pigs fed raw soybeans. Alkali-treated cooked soybeans resulted in poorer performance as compared with cooked soybeans. Soybeans cooked with copper sulfate in the water produced improved gain:feed and gain:protein ratios as compared with cooked soybeans. Copper additions to the diet did not influence pig performance. Energy and protein utilization of the soybean meal and cooked soybean diets was similar and superior to that of raw soybean diets except apparent protein digestibility.