Aspects of gastrointestinal motility in relation to the development of digestive function in neonates

Abstract Gastrointestinal motility is responsible for mixing and transport of digesta and elimination of undigested residues. The basis for the motility is the electrical activity of the gastrointestinal smooth muscle, which has a recurring pattern. In the small intestine of mature animals, this pattern is associated with periodic fluctuations of mesenteric blood flow, and gastric, pancreatic and biliary secretion, and with intestinal absorption. In general, feeding disrupts the cyclic pattern in the stomach and small intestine, replacing it with a continuous post-feeding pattern, and the duration of the post-feeding pattern is dependent on animal species, composition of the diet and feeding regime. The perinatal and weaning periods manifest drastic changes in digestive function and, thus, in gastrointestinal motility. Due to difficulties in performing studies in perinatal and neonatal animals, only few data on the development of gastrointestinal motility, and its synchronisation with other digestive functions, are available. Whereas some studies in the literature indicate that the development of gastrointestinal motility follows the maturation of the regulatory mechanisms, recent data also suggest that changes in gastrointestinal motility around birth and weaning reflect changes in nutrient supply. This paper deals with some aspects of gastrointestinal motility, primarily in the gastric antrum and small intestine, of neonatal animals. Certainly, changes in gastrointestinal motility in early life could be of paramount importance for proper digestive function and this research area requires further attention

Effect of postweaning feed intake on performance, intestinal morphology, and the probability of diarrhoea in piglets

Changes in gastrointestinal architecture, high incidence of diarrhoea, and low feed intake (FI) are commonly observed around weaning of pigs, but the relationship between postweaning FI and diarrhoea is unclear. This study aimed to determine the effect of low or high FI during the first days after weaning on growth performance, diarrhoea probability, intestinal permeability, and morphology in pigs until postweaning day (PWD) 28. A total of 120 pigs (7.20 ± 0.26 kg) weaned at 28 days of age (PWD 0) were randomly allocated to five diets and housed individually until PWD 28. Two diets differed in CP and three diets differed in threonine and tryptophan levels. At PWD 4, pigs with the 25% lowest accumulated FI (LOW; n = 30) and 25% highest accumulated FI (HIGH; n = 30) were selected for the study. Faecal consistency was evaluated daily using a 4-scale visual scoring system. Blood was collected at PWD 4, 14, 21 and 28, and small intestinal and colonic tissue was obtained at slaughter on PWD 28. Until PWD 4, LOW pigs consumed approximately 20% (35.7 ± 5.9 g/day) of the FI of HIGH pigs (181 ± 5.75 g/day; P  0.10). The systemic inflammatory markers haptoglobin and C-reactive protein were higher for HIGH pigs at PWD 4 (P = 0.005), but not affected in the following periods (P > 0.10). Pigs in the HIGH group had an increased area of acidic mucin-producing cells in the small intestine compared with LOW pigs (P < 0.05), but other intestinal morphology measurements at PWD 28 were unaffected by the level of FI. In conclusion, high FI just after weaning was associated with higher growth performance but also higher probability of diarrhoea and more frequent use of antibiotics until PWD 28

Effect of zinc bacitracin and salinomycin on intestinal microflora and performance of broilers

A feeding experiment was carried out over 42 d with four groups of broiler chickens fed experimental diets formulated to provide no supplementation, 20 mg zinc bacitracin, 60 mg salinomycin, or both feed additives in combination. During the fifth week of the experiment, four chickens from each pen were killed, and the contents of gizzard, duodenum, jejunum, ileum, ceca, and rectum were separately collected and pooled. In all intestinal segments, the pH and the concentration of lactic acid were measured, and the numbers of anaerobic bacteria, coliforms, lactic acid bacteria, lactobacilli, enterococci, and Clostridium perfringens were counted. In homogenates of pancreas obtained from four animals, the activities of amylase, lipase, trypsin, and chymotrypsin were measured. A significant growth-promoting effect was observed in the group receiving zinc bacitracin in combination with salinomycin. Zinc bacitracin significantly reduced the number of coliform bacteria in the ileum and increased the activities of amylase and lipase in pancreas homogenates. Supplementation with salinomycin and zinc bacitracin, alone or in combination, resulted in significantly lower counts of C. perfringens as well as Lactobacillus salivarius, which was a dominant lactic acid bacterium found in broiler intestinal contents. High numbers of these lactobacilli may play a role in broiler growth depression related to competition in nutrient uptake or impaired fat absorption due to bile acid deconjugation

An increased weaning age and liquid feed enhances weight gain compared to piglets fed dry feed pre-weaning

Increasing age and providing liquid creep feed could potentially increase the solid feed intake in pre-weaning piglets, which may in turn promote gut maturation and post-weaning feed intake, possibly lessening the severity of the growth-check associated with the suckling-to-weaning transition. Therefore, this study aimed to investigate if feeding dry- versus liquid creep feed (DF vs. LF) and weaning in week 4 or 5 (4W or 5W) could accelerate maturational changes to the small intestines of pre-weaning piglets by increasing digestive and absorptive capacity. In a 2 × 2 factorial study the effect of weaning age (WA) and feeding strategy (FS) on weaning weight, pre-weaning accumulated gain (AG), and average daily gain was measured for 12 923 piglets. A subpopulation of 15 piglets from each treatment group (4WDF, 4WLF, 5WDF and 5WLF; n = 60) were sacrificed to assess the effects of WA and FS on weight of digestive organs, activity of maltase, lactase and sucrase, and gene expression level of sodium-glucose linked transporter 1 (SGLT-1), glucose transporter 2 (GLUT2) and peptide transporter 1 (PepT1) in the proximal part of the small intestine (SI). No interactions were found but average weaning weight was affected by WA (P < 0.001) and FS (P < 0.001), where 5W were heavier than 4W and LF were heavier than DF. Correspondingly, the average daily gain (ADG) was affected by both WA (P = 0.003) and FS (P < 0.001). Only WA affected the relative weight of the digestive organs, where stomach weight, weight of SI and colon weight were heavier in 5W piglets compared to 4W. Lactase activity tended to decrease with age (P = 0.061), but there was no difference in the activity of maltase or sucrase between any of the treatment groups. Similarly, there was no differences in gene expression level of SGLT1, GLUT2 or PepT1 between neither the two ages nor feeding strategies. In conclusion, both WA and FS affect weaning weight and weight gain of piglets in the pre-weaning period

Use of metabolic profile in short-term studies for estimating optimum dietary isoleucine, leucine, and valine for pigs

Traditional AA dose-response studies utilize many animals for evaluation of growth performance, and it is hypothesized that a new experimental design based on modem analytical techniques can reduce the number of used animals. The objective was to evaluate a short-term approach with a low number of pigs based on plasma metabolites as a method to determine the dietary Ile, Leu, and Val requirements. Three separate 6 x 6 Latin square experiments having 6 replicates per treatment were conducted with 6 diets containing increasing concentrations of Ile, Leu, and Val which were fed to 6 pigs (BW 8-9 kg) for 2 days, each without a wash-out period for a period of 12 days. The diets were prepared and used in 3 previous traditional-design dose-response studies and had been stored at 20 degrees C. Blood samples were collected at the end of each 2-day period, and plasma was analyzed for AA and other metabolites using a metabolomics approach. Out of the 18 analyzed plasma AA, 11, 16, and 3 AA for Ile, Leu, or Val, respectively, showed linear or quadratic responses (P < 0.05) which could be linked to animal growth. The same was found for 4 non-AA metabolites in the Ile, and for 7 non-AA metabolites in the Leu study. 3-Methyl-2-oxovaleric acid, ketohexanoic acid, and a-ketoisovaleric acid were discriminating metabolites for both Ile and Leu. It was possible to fit least squares means of 5, 14, and 2 metabolites in the Ile, Leu, and Val experiments to curvilinear-plateau, broken-line, or quadratic models and thereby estimate an optimum dietary BCAA level. The average optimum BCAA levels across metabolites and models were 0.54 standardized ileal digestible (SID) Ile:Lys, 1.04 SID Leu:Lys, and 0.68 SID Val:Lys which were close to optimums of 0.52, 0.93, and 0.70 found in the previous dose response studies based on animal growth performance. In conclusion, certain plasma metabolites could be used to estimate Ile, Leu, and Val requirements, and 2 days of adaptation to a new diet was sufficient to reflect relevant biological changes in the blood to different levels of dietary AA in the current study