The digestion process of the sugar alcohol isomalt in the intestinal tract of the pig. 2. Studies with administration of isomalt as a sweet.

In a study with ten pigs of 60-70 kg live weight, provided with a re-entrant cannula at the end of the ileum, and sixteen intact, non-cannulated pigs, the digestion and absorption of a dietary dose of 100 g isomalt/kg, and isomalt given between the meals as a 'sweet' on the basis of 50 and 100 g/kg feed consumption, were examined. In all three isomalt treatments slightly less than 0.40 of the isomalt consumed was digested in the small intestine when the calculations were based on ileal sugar passage. However, when basing the calculations on energy contents of ileal chyme, only approximately 0.10 was digested in the small intestine. The bacterial fermentation of the isomalt flowing into the large intestine was indicated by a decreased faecal energy digestibility and a slight reduction in faecal dry matter and nitrogen digestibility. The retention of the minerals sodium, potassium, magnesium, calcium and phosphorus was not influenced to any measurable extent when isomalt was fed.

The digestion process of the sugar alcohol isomalt in the intestinal tract of the pig. 1. Studies with administration of isomalt in the feed.

In a study with twelve pigs of 60-70 kg live weight provided with a re-entrant cannula at the end of the ileum, and twelve intact, non-cannulated pigs, the fate of dietary doses of 100 and 200 g isomalt/kg during gastrointestinal passage was examined. From sugar analyses in ileal chyme it was calculated that 0.43 and 0.30 of the isomalt consumed was digested in the small intestine with the 100 and 200 g/kg doses of isomalt respectively. From findings on ileal energy digestibility it was calculated that, because of a secondary effect of isomalt on the digestion of the basal diet, isomalt digestibility in the small intestine was distinctly lower. In faeces no sugars were found, so faecal digestibility of isomalt was 1.00 for both doses. The bacterial fermentation in the large intestine of the isomalt not digested in the small intestine caused an increase in the faecal excretion of nitrogen and energy. This increased faecal excretion was hardly (nitrogen) or not (energy) compensated by a decreased urinary excretion.

Nutritional implications of L-arabinose in pigs.

The pentose sugar L-arabinose is one of the most abundant components released by complete hydrolysis of non-starch polysaccharides of feed ingredients of vegetable origin. Two studies were conducted to investigate the apparent ileal digestibility and urinary excretion of L-arabinose at dietary inclusion levels of 50 and 100 g/kg, and 25, 50, 75 and 100 g/kg respectively, in pigs. As a reference, D-glucose was included in the studies. Water intake, ileal flow of volatile fatty acids and ileal and faecal digestibilities of dietary nutrients in pigs fed on the different diets were also examined. Castrated pigs were prepared with a post-valvular T-caecum cannula to measure ileal digestibility. Faecal digestibility was measured in non-cannulated pigs. Apparent ileal digestibility of L-arabinose was found to be approximately 70%. The presence of L-arabinose in the diet increased ileal flow of volatile fatty acids and lactic acid, suggesting the occurrence of microbial degradation of L-arabinose in the pig small intestine. L-arabinose was partly excreted in the urine. The extent of this urinary excretion as a percentage of intake increased linearly (P < 0.01) as the dietary level increased. In pigs fed on the 25 g L-arabinose/kg diet, 10.9% of the L-arabinose consumed appeared in the urine. This level was increased to 14.7% when pigs were fed on a diet containing 100 g L-arabinose/kg diet. Faecal digestibility and retention of nitrogen decreased significantly in pigs fed on the L-arabinose diets.

Nutritional value of D-xylose and L-arabinose for broiler chicks.

1. Two experiments were conducted to examine the effect of feeding D-xylose and L-arabinose on broiler performance, body composition, caecal length and weight, and liver weight. 2. Graded amounts (25, 50 and 75 g/kg) of D-xylose or L-arabinose were added to either a practical type (Exp. A) or a semi-purified (Exp. B) basal diet. As reference, a diet containing 75 g D-glucose/kg was included in both experiments, which were conducted in battery brooders, the birds receiving the isocaloric [on metabolisable energy (ME) basis] diets as dry mash ad libitum from 6 to 27 d of age. 3. A negative dose-dependent effect of both pentose sugars on weight gain and feed utilisation was observed. The same was true for daily food intake of the D-xylose diets. Water intake increased linearly (P less than 0.05) as the dietary concentrations of both pentose sugars was increased. Consequently, dry matter content of the droppings decreased. 4. Fat content of the chick body tended to decrease when either D-xylose or L-arabinose was included in the diets. 5. Caecal weight was increased markedly by feeding L-arabinose. Liver weight was not affected by feeding either D-xylose or L-arabinose to birds. 6. From data for ME intake and gain in body energy it was estimated that utilisation of the ME of both pentose sugars was inferior to that of D-glucose.

Effect of variable protein contents in diets containing Phaseolus vulgaris beans on performance, organ weights and blood variables in piglets, rats and chickens.

A comparison was made of the effects of antinutritional factors present in Phaseolus vulgaris on piglets, rats and chickens. Also the hypothesis of whether the negative effect on weight gain due to the inclusion of raw Phaseolus vulgaris in the diet can be attributed to an insufficient supply of amino acids was tested. Test diets containing 200 g raw Phaseolus beans/kg were balanced for digestible protein and amino acids; in one diet extra casein was incorporated. The main response criteria were live-weight gain and the weight of various organs including the intestine. Live-weight gain in piglets was markedly reduced during feeding 200 g raw Phaseolus vulgaris/kg in the diet, but not in rats and chickens. Addition of casein did not improve the weight gain of the piglets, indicating that a toxic factor was responsible for the reduced weight gain and not an insufficient supply of amino acids. The weights of the spleen and thymus were markedly reduced in the piglets when the diets with raw Phaseolus beans were given, but not in the rats and chickens. Additional supply of casein did not change this effect. Indications were found that when the supply of dietary protein is adequate there is no reduction in pancreas weight with raw Phaseolus beans as was observed in previous experiments. The weight of the intestine was increased in all three species due to feeding raw Phaseolus vulgaris.

Effect of exogenous porcine somatotropin administration on nitrogen and energy metabolism in three genotypes of pigs.

Effects of exogenous administration of porcine recombinant somatotropin (rpST) on protein gain and metabolic rate were measured in three genotypes (castrated males) of pigs (Pietrain, Duroc and a crossbreed between Dutch Yorkshire and Dutch Landrace). Six pigs of each genotype were assigned at approximately 60 kg to receive pST doses of either 0 (C) or 14 mg (T) administered i.m. twice weekly over 10 wk. Pigs were housed in individual metabolism cages at a room temperature of 20 to 22 degrees C and received feed at 2.6 times maintenance. Protein gain (N x 6.25) was measured over the final 6 wk of the 10-wk test period. For 2 wk in the test period (wk 2 and wk 5), six pigs of each treatment x genotype group were placed in a large respiration chamber and energy balances (in protein and fat) and metabolic rate were measured. Rate of weight gain measured over the final 6 wk of the experimental period increased by 105 g/d (13%) with rpST administration (P less than .01). Daily protein gain over 6 wk was increased by 48 g/animal with application of rpST (P less than .001). There was a genotype x treatment interaction (P less than .01) for protein gain. Daily protein gain in Durocs with pST treatment was increased (39%) more than in crossbreds (31%). Daily fat gain was decreased by 42 g/animal (P less than .001) by T. Daily heat production with rpST was increased by 12 kcal/kg.75, which is comparable to a 12% increase in the maintenance energy requirement.

Sulphur amino acid requirement of laying hens and the effects of excess dietary methionine on laying performance.

Individually-caged laying hens were fed on maize-soya bean meal diets containing 11.50 or 12.35 MJ ME/kg with sulphur amino acid (SAA) contents varying from 5.0 to 7.0 g/kg in period 1 (0 to 20 weeks); from 5.0 to 8.0 g/kg in period 2 (21 to 36 weeks) and from 5.0 to 10.0 g/kg in period 3 (37 to 52 weeks). A SAA requirement of about 750 mg/hen d, of which about 425 mg was methionine, was found to be adequate for birds producing on average 51 g egg mass per hen d over 52 weeks. The SAA requirement was found to be higher for maximum efficiency of food utilisation than for maximum egg yield. A diet containing 140 g protein/kg adequately supplemented with methionine and lysine, could sustain laying performance almost identical to that achieved on a diet containing 167 g protein/kg. In diets with 140 g protein/kg the addition of 0.5 to 3.5 g DL-methionine/kg diet in excess of the requirement did not affect egg production adversely, but food conversion efficiency was decreased.

Failure of dietary-casein-induced acidosis to explain the hypercholesterolemia of casein-fed rabbits.

The partial replacement of casein by a mixture of gelatin, fish protein and soy protein in cholesterol-free semipurified diets of rabbits reduced the hypercholesterolemic response. The partial replacement of casein by the protein mixture also increased the feed intake and alleviated or reversed the weight loss observed from the casein diet. The data indicate that casein alone is not an ideal protein source for rabbits probably because of the imbalance of the amino acid composition. When KCl in the semipurified diets was replaced by KHCO3, a higher feed intake and a better growth were obtained, irrespective of the protein source in the diet. In addition, the feeding of semipurified diets containing KCl resulted in acidosis, which could be prevented by its replacement with KHCO3. A semipurified diet containing casein and KCl produced a more severe acidosis and higher serum cholesterol levels than the diet containing the protein mixture. Nevertheless, the correction of the acidosis by the replacement of KCl in the diet by KHCO3 did not lead to an abrogation of the casein-induced hypercholesterolemia.

Requirement of the hen for sulphur-containing amino acids.

The sulphur amino acid requirements of White Leghorn-type laying hens were determined in two 52-week experiments using diets based on maize and soyabean meal providing from 5.0 to 6.5 g sulphur amino acids/kg, 12.35 MJ ME/kg and 8.6 to 8.8 g lysine/kg. There were six replicates of 15 individually-caged hens each per treatment. 2. A requirement of approximately 775 to 800 mg sulphur amino acids/hen d, of which about 390 to 440 mg was methionine, was found for a maximum of 80 to 83 eggs/100 hen d. There were indications that the requirement for maximum egg production was less than that for maximum efficiency of food utilisation. 3. Diets containing 138 g protein/kg supplemented with methionine and lysine supported production and food utilisation as effectively as a diet containing 167 g protein/kg.

The digestion of yeast cell wall polysaccharides in veal calves.

1. The digestibility of the cell wall polysaccharides of an alkane-grown yeast in different parts of the digestive tract of two veal calves fitted with re-entrant cannulas at the end of the ileum was studied by replacing part of the skim-milk powder of their 'normal', milk-substitute (all-milk-protein) diet by yeast (yeast diet). 2. The lactose and glucose of both the all-milk-protein diet and the yeast diet were almost completely digested before the end of the ileum. During this digestion a small amount of oligosaccharides composed of galactose and glucose was synthesized. These oligosaccharides were digested again in the large intestine. 3. The constituent sugars of the water-soluble fraction of the yeast cell wall carbohydrates were glucose and mannose. The 0-5 M-sulphuric acid-hydrolysate of the water-insoluble fraction contained glucose and mannose and the 12 M-H2SO4-hydrolysate only glucose. 4. Digestibilities measured at the end of the ileum varied considerably between the two animals and averaged only about 0-40. 5. These findings suggest that the cell wall polysaccharides of yeast are digested very little by the normal digestive enzymes of the calf's small intestine, but are used as a substrate by the bacterial flora which are mainly concentrated in the large intestine.

Relation between methionine and inorganic sulphate in broiler rations.

In two experiments with 0-5 weeks old broiler chicks in battery-cages, it was examined whether the requirements for sulphur-containing amino acids in the ration could be reduced by addition of inorganic sulphate. The basal diet was a high energy practical-type broiler ration. The mineral mix included in this diet did not contain sulphates. The basal diet contained 0.73% methionine + cystine. By addition of synthetic methionine, experimental rations with 0.78, 0.82, 0.92 and 1.02% methionine + cystine, respectively, were obtained. The addition of methionine to the basal ration effected significant effects on weight gain (maximum 6-7% at 5 weeks of age) and on feed conversion (maximum 7-8% at 5 weeks of age). The addition of 0.1% Na2 SO4 (=0.068% inorganic sulphate) to the basal and the methionine supplemented diets resulted in an overall increase in weight gain at 5 weeks of age of 0.9% and a reduction in feed conversion of 1.2%; both effects were significant (P less than .05). However, the size of this effect proved to be independent on the contents of sulphur-containing amino acids in the ration. This indicates a small deficiency of the basal ration for inorganic sulphate.

The effect of an anabolic agent on N deposition, growth, and slaughter quality in growing castrated male pigs.

The conversion of feed protein into body protein in growing pigs is rather unfavourable. With Dutch Landrace pigs only 30--40 percent of the digestible crude protein is converted into body protein. To study the influence of implanting 20 mg 17beta-estradiol + 140 mg trenbolone acetate per animal on this conversion ratio, three nitrogen-balance experiments were performed with castrated male pigs of 55--75 kg liveweight. In experiment 3 the energy balance was also measured. N-retention was significantly improved by the treatment. In none of the experiments the digestibility of the ration was influenced. With the pigs implanted at around 55 kg live weight, N-deposition during the period from 6--9 till 26--32 days after treatment was increased by on an average respectively of 24 percent (experiment 1), 60 percent (experiment 2) and 56 percent (experiment 3) as compared with a placebo. Where pigs of 75 kg were implanted, N-deposition was increased over the period from 2 till 28 days after implantation by 39 percent as compared with a placebo. In experiment 3 it was shown that the conversion of the metabolizable energy of the ration into energy deposited in the body (= protein + fat) was not considerably altered at 13--17 days after the treatment of pigs (weighing 55 kg) with anabolic agents. As compared with the placebo, N-deposition was increased by 40 percent and fat deposition was descreased by 15--20 percent. So the implantation with the anabolic agents has resulted in shift to a higher protein deposition and a lower fat deposition. The results of the balance determinations were confirmed in a comparative growth experiment, in which 14 castrated male Large Wht& x Landrace pigs of 56 kg weight (i.e. 69 days before slaughter at 90 kg live weight) were implanted with the aforementioned combination; 14 animals served as control. In the period from treatment till slaughter live weight gain was significantly improved by 6.5 kg; feed conversion was 0.3 units significantly lower than the control. Carcass weight was significantly higher for the treated group (difference compared with control 4.5 kg). Carcass quality was also improved; the carcasses of the treated pigs were longer and the thickness of the backfat was less. In a second comparative experiment on growth of castrated male pigs from 66 to 100 kg, the effect of the oral application of the combination ethinylestradiol (0.6 ppm, 1.2 ppm, and 2 ppm respectively in the feed) and trenbolone acetate (2 ppm in the feed) was studied. The three experimental groups and the control group consisted of 15 animals each. Live weight gain was significantly improved in the two groups with the higher levels of ethinyl estradiol (i.e. 4.4 kg and 6.9 kg respectively), feed conversion was significantly lower in all three anabolic agroups (i.e. 0.2, 0.3 and 0.4 respectively). Backfat thickness was less in all three anabolic groups and the carcasses were longer in the two higher dosage groups compared with the control group...