Exocrine pancreatic secretion is stimulated in piglets fed fish oil compared with those fed coconut oil or lard

Diarrhea induced by insufficient fat absorption in weaned piglets: Causes and nutrition regulation

Fat is one of the three macronutrients and a significant energy source for piglets. It plays a positive role in maintaining intestinal health and improving production performance. During the weaning period, physiological, stress and diet-related factors influence the absorption of fat in piglets, leading to damage to the intestinal barrier, diarrhea and even death. Signaling pathways, such as fatty acid translocase (CD36), pregnane X receptor (PXR), and AMP-dependent protein kinase (AMPK), are responsible for regulating intestinal fat uptake and maintaining intestinal barrier function. Therefore, this review mainly elaborates on the reasons for diarrhea induced by insufficient fat absorption and related signaling pathways in weaned-piglets, with an emphasis on the intestinal fat absorption disorder. Moreover, we focus on introducing nutritional strategies that can promote intestinal fat absorption in piglets with insufficient fat absorption-related diarrhea, such as lipase, amino acids, and probiotics.

Intestinal concentrations of free and encapsulated dietary medium-chain fatty acids and effects on gastric microbial ecology and bacterial metabolic products in the digestive tract of piglets

The influence of low dietary levels of free and encapsulated medium-chain fatty acids on their concentrations in the digesta, the gastric microbial ecology and bacterial metabolic products in the gastrointestinal tract (GIT) in weaned piglets was studied. Starting after weaning, 36 piglets were fed a diet without (Control) or with medium-chain fatty acids uncoated (MCFA) or coated with vegetable fat and lecithin (MCFAc). After 4 weeks, the animals were killed, and digesta from the stomach and different sections of the GIT were collected. The concentrations of caprylic (p < 0.001) and capric (p = 0.001) acids were higher in the stomachs of piglets fed diets MCFA and MCFAc compared to the Control group. The concentrations dropped rapidly along the GIT, regardless of encapsulation, and tended to be higher in groups MCFA and MCFAc compared to the Control. Compared to the Control group, ingestion of diet MCFAc led to an increase in the number of eubacteria (p = 0.001), enterobacteriaceae (p < 0.001), clostridial clusters I (p = 0.001) and IV (p = 0.019), Lactobacillus johnsonii (p < 0.001) and Lactobacillus amylovorus (p = 0.001) in gastric contents. A similar trend was seen with diet MCFA. Relative concentrations of short-chain fatty acids were characterised by lower propionic acid levels (p = 0.045), numerically (p < 0.1) higher acetic, lower n-butyric and i-valeric acid concentrations in the small intestine. Lactic acid concentrations were not significantly changed in the GIT, but ammonia concentrations increased (p < 0.001) in the distal small intestine in the MCFA and MCFAc groups. In conclusion, medium-chain fatty acids affected microbial ecology parameters in the gastric contents and bacterial metabolites in the small intestine. At low dietary levels, medium-chain fatty acids may be regarded as modulators of the gastric microbiota in weaned piglets.

Application of porcine lipase secreted by pichia pastoris to improve fat digestion and growth performance of postweaning piglets

The aim of the study was to use Pichia pastoris to express a recombinant porcine lipase gene (pLip). The expression-secretion cassette was constructed using the P. pastoris GAPDH (glyceraldehyde-3-phosphate-dehydrogenase) promoter and an 89-residue prepro-alpha-factor secretion signal fused to the AOX1 terminator (the pGAPZalphaA vector). A total of 1,408 bp of pancreatic lipase cDNA was produced, which was located from the position of 4-nt upstream of ATG to 1408-nt inside the intact coding region of the pLip sequence. In an animal trial, three concentrations of recombinant lipase activity (0, 5,000 and 10,000 U/kg) were blended with the basal diet and fed to weaned piglets for six weeks. During the experimental period, the growth performance (bodyweight, feed intake, and feed efficiency) of the test groups was superior to that of the control group (p < 0.05). Furthermore, the group fed the diet blended with 10,000 U/kg of recombinant lipase showed significant (p < 0.05) increases in blood triglyceride (TG) concentration on the seventh day postweaning. These results suggested that the porcine lipase protein yielded by transformed yeast cells may improve fat digestibility and enhance the growth performance in postweaning piglets.

No impact of a phytogenic feed additive on digestion and unspecific immune reaction in piglets

Two 35 day experiments were conducted to examine the influence of a commercial phytogenic feed additive (PFA) on nutrient digestibility and unspecific immune reaction of piglets in the post-weaning period. The PFA composition was inulin, an essential oil mix (carvacrol and thymol), chestnut meal (tannins), and cellulose powder as carrier substance. In each experiment, immediately after weaning 40 male castrated piglets were divided into four experimental groups (n = 10). Diets were based on wheat, barley, soy bean meal and fishmeal using lysine as the first limiting amino acid. In experiment 1, graded levels of the PFA were supplied (A: control; B: 0.05% PFA; C: 0.1% PFA; D: 0.15% PFA). Experiment 2 utilized equal diets with 0.1% of the PFA, but different lysine supply (A: control; B: 0.1% PFA; C: +0.35% lysine; D: 0.1% PFA + 0.35% lysine). At the end of the experimental period, acute phase proteins (APPs) haptoglobin and C-reactive protein were examined in individual blood plasma samples. Following each growth study, 16 animals (n = 4) were taken for sampling of ileal chyme and assessing of praecaecal digestibility of protein and amino acids. In addition, digesta samples of the duodenum and the total pancreatic tissue were utilized for determining the enzyme activity of alpha-amylase and trypsin. APP, praecaecal digestibility and enzyme activities did not significantly respond to the PFA supplementaion in diets.

Variations in enzyme activity in stomach and pancreatic tissue and digesta in piglets around weaning

A study was performed to investigate the effect of weaning at 4 weeks of age on the activity of digestive enzymes in the stomach and pancreatic tissue and in digesta from 3 days prior to weaning to 9 days postweaning in 64 piglets. In stomach tissue the activity of pepsin and gastric lipase was determined. Pepsin activity declined abruptly after weaning but 5 days postweaning the weaning level was regained and in the gastric contents no change in pepsin activity was observed. Weaning did not influence the activity of gastric lipase. The activity of eight enzymes and a cofactor was measured in pancreatic tissue. The effect of weaning on the enzyme activity was highly significant for all enzymes except elastase. The activity of all enzymes remained at the weaning level during day 1-2 postweaning followed by a reduction of the activity. The activity of trypsin, carboxypeptidase A, amylase and lipase exhibited minimum activity 5 days postweaning. Trypsin activity increased to the preweaning level on day 7-9 whereas the activity of the others increased but did not reach the preweaning level. The activity of chymotrypsin, carboxypeptidase B and carboxyl ester hydrolase decreased during the entire experimental period. In digesta no effect of weaning was observed on the activity of amylase and trypsin. The activity of chymotrypsin was reduced after weaning in the proximal third of the small intestine and lipase and carboxyl ester hydrolase activity was reduced in the middle and distal parts of the small intestine after weaning. The present study shows that the activities of the digestive enzymes in the pancreatic tissue are affected by weaning. Even though the pancreatic secretion cannot be judged from these results they show that the enzymes respond differently to weaning. In general the activity of the digestive enzymes in pancreatic tissue is low on day 5 postweaning which in interaction with other factors may increase the risk of developing postweaning diarrhoea.

Liver-specific reactivation of the inactivated Hnf-1alpha gene: elimination of liver dysfunction to establish a mouse MODY3 model

Mice deficient in hepatocyte nuclear factor 1 alpha (HNF-1alpha) develop dwarfism, liver dysfunction, and type 2 diabetes mellitus. Liver dysfunction in HNF-1alpha-null mice includes severe hepatic glycogen accumulation and dyslipidemia. The liver dysfunction may appear as soon as 2 weeks after birth. Since the HNF-1alpha-null mice become diabetic 2 weeks after birth, the early onset of the liver dysfunction is unlikely to be due to the diabetic status of the mice. More likely, it is due directly to the deficiency of HNF-1alpha in liver. Although the HNF-1alpha-null mice have an average life span of 1 year, the severe liver phenotype has thwarted attempts to study the pathogenesis of maturity-onset diabetes of the young type 3 (MODY3) and to examine therapeutic strategies for diabetes prevention and treatment in these mice. To circumvent this problem, we have generated a new Hnf-1alpha mutant mouse line, Hnf-1alpha(kin/kin), using gene targeting to inactivate the Hnf-1alpha gene and at the same time, to incorporate the Cre-loxP DNA recombination system into the locus for later revival of the Hnf-1alpha gene in tissues by tissue-specifically expressed Cre recombinase. The Hnf-1alpha(kin/kin) mice in which the expression of HNF-1alpha was inactivated in germ line cells were indistinguishable from the HNF-1alpha-null mice with regard to both the diabetes and liver phenotypes. Intriguingly, when the inactivated Hnf-1alpha gene was revived in liver (hepatic Hnf-1alpha revived) by the Cre recombinase driven by an albumin promoter, the Hnf-1alpha(kin/kin) mice, although severely diabetic, grew normally and did not develop any of the liver dysfunctions. In addition, we showed that the expression of numerous genes in pancreas, including a marker gene for pancreas injury, was affected by liver dysfunction but not by the deficiency of HNF-1alpha in pancreas. Thus, our hepatic-Hnf-1alpha-revived mice may serve as a useful mouse model to study the human MODY3 disorder.