Microbial and nutritional aspects of feeding fermented feed (poultry by-products) to pigs.

Broiler by-products (heads, feet, and viscera) mixed with 4% dextrose were pasteurized for 4 min at 90 degrees C core temperature, cooled to 20 degrees C, and fermented with Lactobacillus plantarum as starter culture. These fermented poultry by-products were fed to 12 individually housed fattening pigs as part (17.6% of the dry matter) of their fattening ration, the remainder composed of compound pig feed. Control pigs received a compound pig feed only. Both groups of pigs were fed restrictively on the basis of body weight. The technical results of the pigs fed the experimental diet showed a significantly improved feed:gain ratio (2.46 vs 2.57), a significantly higher carcass weight (86.1 vs 81.8 kg), a lower meat percentage (50.9 vs 52.5%) and an increased backfat thickness (21.5 vs 18.7%). The bacterial flora in the intestinal tract of the pigs fed the experimental diet differed significantly from the control animals. Decreased colony counts of mesophilic aerobic bacteria, Enterobacteriaceae, enterococci and lactobacilli were found in the rectal content and the prevalence of salmonella was lower. It is suggested that the improved feed:gain ratio and the reduced bacterial activity of the measured groups of bacteria is a result of 1) the higher energy content of the diet, and(or) 2) an assumed enhanced digestibility of nutritional components in the diet, and(or) 3) the lower incidence of diarrhea in the pigs fed with fermented poultry by-products. This resulted in a lower contamination level of enteropathogenic bacteria like, salmonella and Escherichia coli, in the gastro-intestinal tract of the pigs fed fermented poultry by-products.

Treatment of dietary casein with formaldehyde reduces its hypercholesterolemic effect in rabbits.

Rabbits were fed cholesterol-free, semipurified diets containing 42% (wt/wt) casein or 21% casein plus one of the following nitrogen sources: soy isolate, amino acid mixture simulating casein, amino acid mixture simulating soy isolate, formaldehyde-treated casein or formaldehyde-treated soy isolate. Two additional groups of rabbits were fed the 42% casein diet and the diet containing casein plus soy isolate to which 0.4% (wt/wt) pure formaldehyde was added, this amount being identical to the amount of formaldehyde present in the diets with formaldehyde-treated proteins. Growth was somewhat reduced on the three diets containing 42% casein. The diet containing 42% casein to which no formaldehyde had been added induced severe hypercholesterolemia, the level of serum cholesterol after 8 weeks being about 10 mmol/L. The hypercholesterolemia was markedly reduced by the replacement of half of the casein by soy isolate, formaldehyde-treated soy isolate or formaldehyde-treated casein. No significant reduction of the concentration of serum cholesterol was seen when half of the 42% casein was replaced by an amino acid mixture imitating either casein or soy isolate. Formaldehyde per se did not significantly influence the level of serum cholesterol. We conclude that the differential tertiary structure of intact casein and soy isolate is an important factor in determining the cholesterolemic responses in rabbits to these proteins.

Cholesterol concentration and lipoprotein pattern in the serum of veal calves fed milk replacers with various levels of cholesterol.

Veal calves, aged about 1 week, were fed for 146 days milk replacement diets supplemented with various levels of cholesterol. Four groups consisting of 11 or 12 animals received diets to which 0, 0.19, 0.56 or 0.93% (on the basis of air-dry matter) cholesterol was added at the expense of fat. Cholesterol feeding significantly increased the level of serum cholesterol. This increase was either linear or S-shaped over the entire range of cholesterol feeding, depending on the time during which the calves were fed the diets. In the calves fed cholesterol, the ratio of free to esterified cholesterol in the serum was significantly increased. The ingestion of cholesterol markedly increased the cholesterol content of the VLDL, IDL and LDL fractions in the serum. When compared to the 0.56%-cholesterol diet, the inclusion of 0.93% cholesterol in the diet did not further increase the cholesterol concentrations in the IDL and LDL fractions. Upon density gradient ultracentrifugation of serum prestained for lipid with Sudan Black, it was observed that dietary cholesterol caused the HDL1 particles (1.063 less than d less than 1.092) to to shift towards a lower density range. Cholesterol feeding effected an increase in the level of serum triglycerides, the increase being already maximal with 0.19% cholesterol in the diet. Dietary cholesterol induced elevated concentrations of serum phospholipids, the elevation being proportional to the amount of cholesterol in the diet.

Diurnal patterns of the concentrations of cholesterol, triglycerides, glucose, nonprotein nitrogen and urea in the serum of veal calves fed a milk replacer supplemented with cholesterol.

Veal calves (aged about 9 weeks; three animals per group) were fed twice a day liquid diets containing 60% skim milk powder and 20% crude fat (w/w) for 7.5 weeks. Addition of 1% cholesterol to the diet, at the expense of fat, caused a 70% increase in the level of serum cholesterol. Both in the control and cholesterol-fed calves, no diurnal rhythm in the concentration of cholesterol in the serum was observed. Serum triglycerides were not clearly elevated after feeding, but a steady increase during the day was observed, the increase being similar in both dietary groups. Cholesterol feeding seemed to induce lower postprandial levels of urea and higher levels of amino acid nitrogen, but this was only observed after feeding in the morning (8.00 a.m.), but not after feeding in the evening (8.00 p.m.). Dietary cholesterol significantly elevated postprandial glucose levels in veal calves. It is suggested that hypercholesterolemia effects an impaired glucose tolerance, possibly also in man.