Intestinal barrier function and absorption in pigs after waeaning: a review

Under commercial conditions, weaning of piglets is associated with social, environmental and dietary stress. Consequently, small-intestinal barrier and absorptive functions deteriorate within a short time after weaning. Most studies that have assessed small-intestinal permeability in pigs after weaning used either Ussing chambers or orally administered marker probes. Paracellular barrier function and active absorption decrease when pigs are weaned at 3 weeks of age or earlier. However, when weaned at 4 weeks of age or later, the barrier function is less affected, and active absorption is not affected or is increased. Weaning stress is a critical factor in relation to the compromised paracellular barrier function after weaning. Adequate feed intake levels after weaning prevent the loss of the intestinal barrier function. Transcellular transport of macromolecules and passive transcellular absorption decrease after weaning. This may reflect a natural intestinal maturation process that is enhanced by the weaning process and prevents the pig from an antigen overload. It seems that passive and active absorption after weaning adapt accurately to the new environment when pigs are weaned after 3 weeks of age. However, when weaned at 3 weeks of age or earlier, the decrease in active absorption indicates that pigs are unable to sufficiently adapt to the new environment. To improve weaning strategies, future studies should distinguish whether the effect of feed intake on barrier function can be directed to a lack of a specific nutrient, i.e. energy or protein

Nutrition driven small-intestinal development and performance of weaned pigs and young broilers

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

Nutrition driven small-intestinal development and performance of weaned pigs and young broilers

<p> 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.</p

Small intestine development in chicks after hatch and in pigs around the time of weaning and its relation with nutrition: A review

The period after hatch in broilers and around the time of weaning in pigs is critical for development and for adaptation of the small intestine to the nutritional changes. In broilers, the small-intestinal weight relative to body weight and villous height increase rapidly during the first week after hatch. After the first week, the relative small-intestinal weight decreases gradually, but the villous height continues to increase. In pigs, at 4 d after weaning, villous height decreases to about 60% of the pre-weaning height when weaned between 1 and 4 wk of age. Two weeks after weaning, this recovers to similar values as in unweaned control animals independent of weaning age. Small-intestinal development after hatch and after weaning consistently deteriorates at low feed intake levels and with suboptimal protein nutrition. These findings stress the importance of applying an optimal nutritional strategy in these phases of life to reach optimal small-intestinal development

Dietary amino acid levels and feed restriction affect small intestinal development, mortality, and weight gain of maile broilers

This study investigated the effect of 2 different dietary amino acid treatments and feed restriction in early life versus a control treatment on development of the small intestine segments (weights), mortality, and broiler performance. Each treatment was applied to 6 cages with Ross 308 male broilers and to 6 cages with Cobb 500 male broilers with 24 birds per cage. A control treatment (100% ideal protein) was compared with a treatment with 30% extra ideal protein, a treatment with daily adjustment of the dietary amino acid level and profile, and a feed restriction treatment. The protein treatments were applied from 0 to 14 d of age. The feed restriction was applied from 4 to 21 d of age. Restriction was 15% from d 4 to 14 of age and diminished with equal daily steps thereafter to 5% at 21 d of age. Birds were weighed and dissected for evaluation of small intestine weights at 6, 9, 14, and 36 d of age. Feed intake restriction reduced leg problems in Ross and Cobb broilers. Extra dietary protein reduced leg problems in Ross broilers only. The present experiment does not show that small intestinal weight development is related to mortality. Thirty percent extra dietary ideal protein increased duodenum weight between 6 and 9 d of age. This was not further increased by the daily optimization of the dietary amino acid level and profile. The increased duodenum weights coincided with an improved BW gain. This indicates that duodenum weight may be important in facilitating BW gain in young broilers. Thus, it may be worthwhile to pay more attention to the relation between nutrition and duodenum weight and duodenum function in further studies

Intestinal barrier function and absorption in pigs after waeaning: a review

Under commercial conditions, weaning of piglets is associated with social, environmental and dietary stress. Consequently, small-intestinal barrier and absorptive functions deteriorate within a short time after weaning. Most studies that have assessed small-intestinal permeability in pigs after weaning used either Ussing chambers or orally administered marker probes. Paracellular barrier function and active absorption decrease when pigs are weaned at 3 weeks of age or earlier. However, when weaned at 4 weeks of age or later, the barrier function is less affected, and active absorption is not affected or is increased. Weaning stress is a critical factor in relation to the compromised paracellular barrier function after weaning. Adequate feed intake levels after weaning prevent the loss of the intestinal barrier function. Transcellular transport of macromolecules and passive transcellular absorption decrease after weaning. This may reflect a natural intestinal maturation process that is enhanced by the weaning process and prevents the pig from an antigen overload. It seems that passive and active absorption after weaning adapt accurately to the new environment when pigs are weaned after 3 weeks of age. However, when weaned at 3 weeks of age or earlier, the decrease in active absorption indicates that pigs are unable to sufficiently adapt to the new environment. To improve weaning strategies, future studies should distinguish whether the effect of feed intake on barrier function can be directed to a lack of a specific nutrient, i.e. energy or protein

Lactulose as a marker of intestinal barrier function in pigs after weaning

Intestinal barrier function in pigs after weaning is almost exclusively determined in terminal experiments with Ussing chambers. Alternatively, the recovery in urine of orally administered lactulose can be used to assess intestinal permeability in living animals. This experiment was designed to study the barrier function of the small intestine of pigs over time after weaning. The aim was to relate paracellular barrier function (measured by lactulose recovery in the urine) with macromolecular transport [measured by horseradish peroxidase (HRP) using Ussing chambers] and bacterial translocation to assess whether lactulose recovery is related to possible causes of infection and disease. Forty gonadectomized male pigs (6.7 ± 0.6 kg) were weaned (d 0) at a mean age of 19 d, fitted with urine collection bags, and individually housed. Pigs were dosed by oral gavage with a marker solution containing lactulose (disaccharide) and the monosaccharides l-rhamnose, 3-O-methylglucose, and d-xylose at 2 h and at 4, 8, and 12 d after weaning. The recovery of sugars in the urine was determined over 18 h after each oral gavage. The day after each permeability test, the intestines of 10 pigs were dissected to determine bacterial translocation to the mesenteric lymph nodes and jejunal permeability for HRP in Ussing chambers. Recovery of l-rhamnose in urine was affected by feed intake and by the time after weaning (P = 0.05). Recovery of lactulose from the urine was greater (P = 0.05) at 4, 8, and 12 d after weaning compared with the first day after weaning and was negatively correlated with feed intake (r = -0.63, P = 0.001). The mean translocation of aerobic bacteria to the mesenteric lymph nodes was greater at 5 and 13 d after weaning compared with d 1 (P = 0.05). Lactulose recovery showed no correlation with permeability for HRP nor with bacterial translocation (P > 0.05). Although both lactulose recovery and bacterial translocation increased over time after weaning, lactulose recovery did not correlate with the permeability for HRP nor bacterial translocation within a pig (P > 0.05). Therefore, we conclude that lactulose recovery in the urine of pigs after weaning is not associated with risk factors for infections. However, it appears to be possible to measure paracellular barrier function with orally administered lactulose in pigs shortly after weaning. Further studies will reveal whether this variable is relevant for the long-term performance or health of pigs after weanin