Monensin was fed at levels of 0 and 33 ppm in a series of experiments to determine its effect on nitrogen (N) utilization by steers fed diets high in sorghum grain (76%, steam-processed, flaked) and corn (90%, whole shelled). Total ruminal volatile fatty acid (VFA) concentrations measured 3 hr postprandially were not affected by monensin addition to either diet. Molar proportion of acetic acid decreased (P < .05) was observed with monensin addition to the sorghum grain-based diet. Monensin had no effect on apparent total tract digestibility of dry matter or energy in either diet, but consistently improved apparent total tract digestibility of crude protein (CP) in both diets. Improvement was greater (P < .05). Retention of N tended (P > .05) to improve in response to monensin with the sorghum grain-based diet (24 vs 20% of N intake; 41 vs 36% of N absorbed). Ruminal ammonia concentrations measured 3 hr post-prandially were decreased (P < .10) ruminal digestion of feed N (44 vs 51%) for steers fed monensin. Monensin decreased (P < .05) the contibution of bacterial N (42 vs 50%) and increased (P < .05) that of ruminally undegraded feed (bypass) N (58 vs 50%) to total N digested postruminally, resulting in less (P < .10) bacterial N (23 vs 28 g/day) and a tendency (P > .10) for more feed bypass N (32 vs 27 g/day) to be digested in the intestines of steers fed monensin with the corn-based diet. That monensin caused a greater proportion of feed OM and N to be digested and absorbed in the intestines than in the rumen (with possibly greater resultant metabolic efficiency) may account for some of the benefit of feeding this compound with high grain diets, as losses incurred in the ruminal transformation of feed nitrogen to bacterial nitrogen appear to be partially eliminated.

No description available.

The influence of microbial phytase on growth performance, availability of macro and trace minerals, apparent ileal digestibility (AID) and apparent "fecal" digestibility (AFD) of amino acids (AA) and CP were investigated. The optimum level of dietary Ca and P for the maximum efficacy of supplemental phytase in broiler chickens was also studied. Phytase supplementation (600 U/kg) to a low P diet increased $(P 0.05)$ on feed efficiency in broiler chickens at 21 d. The efficacy of phytase, particularly in stimulating growth, was higher in male than female chickens. The relative retention of Ca, P, Cu, Zn and N increased by addition of phytase to a low P diet but phytase had no effect $(P >0.05)$ on the retention of Mg, Mn and Fe. Phytase supplementation increased $(P 0.05)$ on plasma Zn, Cu, and Mg. Phytase increased $(P 0.05)$ on mineral proportions in the tibia ash; however, it increased $(P 0.05)$ on AID of any of the AA in male chickens. Addition of phytase did not have any effect $(P > 0.05)$ on AFD of any of the AA in male chickens but increased $(P 0.05)$ on either AID or AFD of CP and AA at 21-d. In summary, phytase supplementation increased the growth performance, availability of P, Ca, Cu, Zn and N, plasma P, and tibia ash and reduced plasma Ca; it also increased the AID and AFD of most of the AA, particularly in female chickens at 28-d. The efficacy of microbial phytase was high when dietary P and Ca levels were low.

No description available.

Raspberry pomace, consisting of seeds, pulp and added rice hulls, is the residue from the pressing of raspberries for juice and concentrate production. Through the determination of chemical composition by laboratory analyses and the measurement of feeding value in animal trials, the pomace was evaluated as a feedstuff for growing pigs. Pomace contains 11.1% crude fat, 10.0% crude protein, 59.5% total dietary fibre, 7.4% soluble carbohydrates, and a gross energy level of 5220 kcal*kg⁻¹. The acid detergent residue of the pomace contains 11.7% lignin, 6.0% cutin, 2.2% acid detergent ash and 26.0% cellulose (by difference). The digestibility of dry matter, fat, protein and energy was determined. Pomace dried at 60 C, whole and ground (1mm) was fed to growing male pigs (30-35 kg) in a replicated 4X4 Latin Square design with treatments basal (B) , B plus 40% unground pomace, B plus 40% ground pomace and B plus 40% barley. Grinding of pomace significantly improved the digestibility of all parameters measured, however, the barley-soybean meal basal ration was consistently better digested than either of the pomace treatments. The digestibility of whole and ground pomace was respectively: dry matter 10.7% and 20.8% (S.E.M. 1.30), fat 24.1% and 79.7% (S.E.M. 3.47), protein 10.6% and 14.7% (S.E.M. 4.83) and energy 7.9% and 28.4% (S.E.M. 1.80). Protein quality of ground (1mm) and freeze-dried pomace was evaluated with rats in metabolism cages to produce the following values: true protein digestibility 36.0% (S.E.M. 0.66), biological value 91.0% (S.E.M. 3.46), and net protein utilization 32.7% (S.E.M. 1.15). In rat growth trials, where pomace replaced barley incrementally, growth rate was not affected at replacement levels up to 40%, although feed efficiency declined consistently as the level of pomace in the diet increased. It is suggested that raspberry pomace could replace up to 20% of an energy feedstuff in a ration for growing swine without significantly reducing growth rate or feed efficiency. / Land and Food Systems, Faculty of / Graduate

The objectives o-f this research were to investigate the effects of blending Canbra or Canola oil with other oils or fats on the nutritive value and autoxidative stability of the blended oils, and to investigate the possibility of using hydrolyzed oils (free fatty acids) in the study of fatty acid balancing. Canbra oil (containing 6.1% erucic acid) was blended with sunflower oil or animal lard 1/1 (w/w). Canola oil (0.55% erucic acid) was blended with sunflower oil in the ratios 9/1, 8/2, 7/3, 6/4 and 5/5. The nutritional value was assayed using growing chicks fed lipid at 3% in a practical diet during a 4 week feeding period. Evaluation was made using body weight, weight gain, feed consumption, feed conversion, feed digestibility, lipid digestibility, total fatty acid digestibility, metabolizable energy and individual fatty acid digestibility. Results show that Canbra oil is equivalent to animal lard but significantly inferior to sunflower oil. Blending Canbra oil and sunflower oil or animal lard improved chick growth and fatty acid utilization over that demonstrated by the Canbra oil alone. Canola oil was equivalent to sunflower oil and soybean oil in supporting chick growth. The 7/3 and 5/5 blends showed synergistic improvement in promoting growth, fatty acid, protein and metabolizable energy utilization. It was concluded that Canola oil is nutritionally equivalent to either sunflower oil or soybean oil and that blending with sun-flower oil further improved its nutritional value. Oil blending rendered no significant detrimental effects on stability. The fatty acids of hydrolyzed Canola and sunflower oil showed nutritive performance equivalent to that of the intact oils. The fatty acids of a hydrolyzed 5/5 blend of Canola oil and sunflower oil showed reduced absorption of some fatty acids and the fatty acids of hydrolyzed soybean oil showed reduced diet and fatty acid absorption relative to the intact oils. These results demonstrate that feeding hydrolyzed oils may be a useful method of investigating fatty acid balance but more research is required in this area. / Land and Food Systems, Faculty of / Graduate

No description available.

Three studies were conducted to evaluate a method for estimating grass and legume fractions in extrusa samples from esophageally-fistulated animals, based on different concentrations of neutral detergent fiber (NDF), Ca and lignin in grasses and legumes. In experiment 1, NDF, Ca and lignin concentrations were measured in mixtures of six combinations of red clover-orchardgrass and alfalfa-tall fescue (100:0; 80:20; 60:40; 40:60; 20:80; 0:100). The R² values were .90, .80 and .22 for Ca, NDF and lignin, respectively. In experiment 2, fresh tall fescue and red clover were collected during 8 d, mixed in the same proportions as in experiment 1, and each fraction was fed to esophageally-fistulated steers. Extrusa samples were collected without loss of saliva. Regression equations developed were y= 1.08 - .008x (R²= .91) for Ca and y= 50.9 + .22x (R²= .74) for NDF, where x represents % grass. In experiment 3, two esophageally-fistulated steers were allowed to graze in 20 4 X 4 m² plots of red clover and tall fescue after fasting overnight. The grass/legume proportions of the extrusas and the grab samples were extrapolated from slopes. The botanical composition of grab samples differed (P<.001) from that of extrusas for both components and for both animals. Extrapolation from NDF values tended to overestimate the proportion of grass in extrusa samples and underestimate it in grab samples. Calcium was not affected by salivation and mastication and was more reliable than NDF. Lignin was not an accurate predictor. / M.S.

Carnosine and methionylglycine (using ³⁵S-methionylglycine as a representative marker) absorption and transfer across ruminal and omasal epithelia collected from four (carnosine) and seven (methionylglycine) sheep were studied using parabiotic chambers that were repeatedly sampled over a 240-min incubation. The quantity of dipeptide absorbed or transferred was linearly (P < .01) dependent on substrate concentration. Carnosine was transferred intact across both tissues. More carnosine was absorbed (P < .02) and transferred (P < .01) by the omasal epithelia. Methionylglycine was transferred intact across both tissues, but less (P < .01) remained intact in serosal buffer after 240 min incubation with omasal epithelium than with ruminal epithelium. The amount of methionylglycine that accumulated in each tissue was similar. Methionylglycine accumulation in tissues plus transfer after 240 min was greater (P < .01) for omasal tissue. The ability of sheep ruminal and omasal epithelia to absorb and transfer carnosine and methionylglycine in parabiotic units was demonstrated. Dipeptide translocation across forestomach epithelial tissues, which has not been reported previously, may be an important route for supplying dietary amino acids to the ruminant. / Master of Science

Fifteen abomasally cannulated, growing wether lambs were used in two metabolism studies to evaluate the utilization of RNA and DNA. Wethers were blocked by weight and breeding and randomly assigned within block to one of five treatments with the restriction that no animal receive the same treatment in both trials. All animals were fed 350 g, twice daily, of a basal ration supplying 7.1 g nitrogen. In addition, the lambs received twice daily infusions of either soy protein, RNA, DNA, or a 1:1 combination of RNA and DNA or a sham infusion. Tris buffer was used as the solvent for RNA and DNA, the carrier for soy protein and the sham infusion. Infusions, except for the sham, were calculated to be isonitrogenous supplying 2.5 g nitrogen per day. Following a 10-day preliminary period, all urine and feces were collected during a 10-day collection period. Jugular blood was obtained at 6 and 12 hr post feeding on the last day of each trial. Crude protein digestibility was significantly elevated for the nucleic acid infusions over that for the sham. The RNA value, though not different from DNA or the combination, was comparable to that for the soy. Calculated by difference, the absorption values of RNA, DNA, and the combination of RNA and DNA were 97, 77, and 72%, respectively. Nitrogen retention, expressed in g/day, tended to be higher for the nucleic acids than for the sham. The combination of RNA and DNA was not different from the soy treatment which had the highest (P< .05) nitrogen retention. Urinary urea, allantoin, and ammonia levels were elevated (P <.05) for the nucleic acid treatments over the sham. Urinary creatinine and “other” nitrogen (nitrogen unaccounted for) were not affected by treatment. Blood urea.nitrogen tended to be higher for the combination of RNA and DNA than the sham, while RNA, DNA, and the soy treatments were higher (P <.05) than the sham. Serum protein concentrations were unaffected by treatment. The amino acid concentrations either tended to be higher or were higher for the nucleic acids, especially the RNA and combination of RNA and DNA, than for the sham. Concentrations for the nucleic acid treatments compared well with those for the soy treatment and in some cases were higher than the soy. From these data, the following conclusions were made: 1) nucleic acids are well digested and absorbed; 2) retention and utilization of nitrogen from nucleic acids appears to be minimal; 3) the majority of the absorbed nucleic acids are excreted as urea and allantoin; and 4) essential and non-·essential plasma free amino acids are increased by exogenous nucleic acids. The effect may be influenced by urea recycling to the rumen as the result of nucleic acid degradation. Urea recycling would stimulate microbial growth with consequent increases in microbial amino acid synthesis. Amino acids associated with the urea cycle were noted to be affected. / Master of Science