|Title||Nutrition driven small-intestinal development and performance of weaned pigs and young broilers|
|Source||University. Promotor(en): Martin Verstegen; Wouter Hendriks, co-promotor(en): H.B. Perdok. - S.l. : s.n. - ISBN 9789085859406 - 135|
|Publication type||Dissertation, internally prepared|
|Keyword(s)||biggen - vleeskuikens - jonge dieren - dunne darm - ontogenie - diervoeding - voedingsstoffen - eiwitgehalte - prestatieniveau - dierlijke productie - piglets - broilers - young animals - small intestine - ontogeny - animal nutrition - nutrients - protein content - performance - animal production|
|Categories||Animal Nutrition and Feeding (General) / Farm and Captive Animals (General)|
The relative importance of animal husbandry and nutrition during the first weeks after weaning in pigs and after hatch in broilers has increased considerably over the past 50 years as a result of the tremendous improvement in daily body weight (BW) gain. Substantial changes in weight, architecture, and physiology of the small intestine occur early in the life of these animals. The optimal function of the small intestines is fundamental for nutrient absorption from the diet and for health. Nutrient requirement studies conducted on these animals have largely overlooked the very young animal. It is therefore logical that there are still gaps in our knowledge of the nutrition of these animals during this particular stage of life. The objective of this thesis was to improve small-intestinal development and performance of pigs after weaning and young broilers by ways of an optimal nutrient composition of the diet. In experiments with broilers, it was shown that enhanced dietary ideal protein (IP) concentrations in the starter diet increased BW gain in the starter phase and in the subsequent grower phase. Moreover, the effects of enhanced IP concentrations in the starter diet on BW gain are more marked than the effects in the grower and finisher diets. However, BW gain hardly improved in response to dietary IP increment during the first 3 d after hatch, whereas in the consecutive 3 d, BW gain improved substantially with enhanced dietary IP concentrations. This suggests that the first 3 d after hatch, from a nutritional point of view, are substantially different from the next consecutive days in the life of broiler chicks. Moreover, a 30% increase in dietary IP increased the duodenum weight between 6 and 9 d of age. Thus, in young broilers, a greater relative small-intestinal weight is associated with a greater BW gain. However, this thesis did not make a clear determination of the functional changes of the small intestine after hatch in broilers. A review of the literature showed that after weaning in pigs, the barrier function of the tight junctions of the small intestine is disturbed, and transcellular barrier function seems to improve after weaning. In the first study with pigs, the data here showed that paracellular barrier functions, as measured with orally administered lactulose, did not correlate with bacterial translocation or transcellular barrier function, as measured with horseradish peroxidase in Ussing chambers. Therefore, it was concluded that lactulose recovery in the urine of pigs after weaning is not associated with risk factors for infection. The last study with pigs showed that dietary protein with dextrose stimulates mucosal weight after weaning. However, the combination of protein with dextrose had no substantial effect on small-intestinal barrier function, whereas dietary starch with dextrose improved small-intestinal barrier function. In conclusion, optimising protein nutrition in broilers after hatch has a great potential to further improve overall broiler performance. In particular, knowledge regarding optimal nutrition during the first 3 d after hatch is still lacking. Furthermore, dietary protein is a potent stimulator for growth of the proximal small intestine in broilers and of the small-intestinal mucosa in pigs. However, mucosal mass and luminal protein are of minor importance for small-intestinal barrier function in pigs after weaning. In contrast, the luminal carbohydrate supply or energy level is important for maintaining small-intestinal barrier function.