Ornithine metabolism, but not arginine synthesis, is affected by the addition of ornithine to an arginine-deficient diet in enterally-fed piglets

In a previous study, ornithine addition to an arginine-deficient diet did not improve whole-body arginine status in enterally-fed piglets; however, the metabolic fates of the supplemental ornithine were not studied. This experiment determined the metabolic fates of the supplemental ornithine and whether ornithine metabolism was affected by the addition of -ketoglutarate. Male piglets (n = 20, 1.8 kg), fitted with gastric catheters for diet and isotope infusion, portal vein catheters for isotope infusion and femoral vein catheters for blood sampling (d 0), received 2 d of a complete diet, followed by 5 d of 1 of 4 test diets: the arginine-deficient diet (basal), or the basal diet with either -ketoglutarate [ +  - KG; 4.6 mmol/(kg d)], ornithine [ + Orn; 9.2 mmol/(kg d)] or both [ +  - KG/ + Orn; 4.6 mmol/(kg d)  - ketoglutarate + 9.2 mmol/(kg d) ornithine]. Piglets received primed, constant infusions of [1-¹⁴C]ornithine infused intragastrically (either d 5 and d 7) to determine ornithine kinetics, and [guanido-¹⁴C]arginine intragastrically to measure arginine flux (d 6). Piglets receiving the ornithine-containing diets had a higher intragastric ornithine flux (P < 0.0001) and ornithine oxidation (P < 0.05). Ornithine supplementation did not increase arginine synthesis, although the ornithine supplemented piglets had a greater conversion of ornithine to proline (P < 0.0001). The fates of supplemental ornithine in piglets fed an arginine-deficient diet appear to be oxidation and proline synthesis; this was not affected by the presence of -ketoglutarate.     

Gut growth and glucose tolerance in newborn pigs subjected to prenatal protein restriction and postnatal Glucagon-like Peptides

Fetal protein restriction is potentially associated with organ dysfunctions after birth (e.g. impaired gut growth, glucose tolerance and pancreatic β-cell function). Just after birth, gut growth and maturation is stimulated by enteral food intake, and inhibited by total parenteral nutrition (TPN), in part mediated via differential release of insulino- and intestino-tropic hormones like the Glucagon-Like Peptides 1 and 2 (GLP-1, GLP-2). We hypothesized that short-term co-infusion of GLP-1 and GLP-2 would stimulate pancreatic and intestinal growth in newborn TPN-fed pigs subjected to prenatal protein restriction. Two sows were fed a protein-restricted diet (PR: 8% crude protein during last 50% of gestation) while a third sow was fed a control diet (C: 15% crude protein). PR pigs were killed either at birth (n = 7) or after 3 days TPN with (n = 6) or without (n = 4) intravenous infusion of a mixture of synthetic human GLP-1_7–37 and GLP-2_1–33 (each 50 μg/kg/d). At birth, PR piglets did not show reduced body weight, relative to controls (1.45 vs. 1.50 kg), but significantly reduced weight of the small intestine (18.0 ± 0.6 vs. 21.9 ± 0.5 g/kg, P < 0.001) and a marginally reduced pancreas weight (0.85 ± 0.02 vs. 0.93 ± 0.04 g/kg, P = 0.10). Co-infusion GLP-1 and GLP-2 into PR pigs resulted in increased basal glucose levels (5.3 vs. 4.0 mM), and glucose-stimulated insulin release, but did not have any significant effect on body weight, or weight of internal organs (heart, lungs, spleen, kidneys, adrenals, stomach, colon, liver, intestine, pancreas). We conclude that short-term (3 days) infusion of native GLP-1 and GLP-2 does not stimulate gut growth or glucose tolerance in TPN-fed piglets born from protein-restricted mothers. Moderate maternal protein restriction does however cause significant reduction in intestinal growth in newborn piglets which may decrease the neonatal digestive capacity.     

Microbial activity in the gut of piglets: II. Effect of fibre source and enzyme supplementation

Twenty four Duroc × Landrace male piglets, aged 21 days, were assigned to 1 of 4 experimental diets. Diets 1 and 2 contained 150 g kg^− 1 wheat bran and diets 3 and 4 contained 90 g kg^− 1 maize cobs as the major fibre source. All diets contained 480 g kg^− 1 wheat and 200 g kg^− 1 soybean meal. Diets 2 and 4 were supplemented with the following enzyme complex: 800 U/kg cellulase, 1800 U/kg glucanase and 2600 U/kg xylanase.

The replacement of wheat bran by maize cobs increased the acetic (P < 0.05) and decreased the butyric acid production (P < 0.05) in the cecum. Piglets fed diets with maize cobs had lower (P < 0.05) levels of butyric acid in the colon than those fed wheat bran.

The xylanolytic, pectinolytic and cellulolytic enzyme activities were higher (P < 0.05) in the cecum and colon of piglets fed the wheat bran based diets. The supplementation of the diet with the enzyme complex did not significantly affect the levels of short chain fatty acids formed in the small intestine and there was a non significant increase of the levels of acetic, propionic and butyric acids in the cecum and colon of piglets (P < 0.10). No interactions were present between fibre sources and enzyme addition.

The results suggest that the enzyme supplementation of the diet did not bring significant benefits to the animals and that when maize cobs replaces wheat bran in diets it negatively affects butyric acid production and fibre-degrading enzyme activity in the hindgut of piglets.     

Effects of low-protein diets supplemented with crystalline amino acids on performance and intestinal development in piglets over the first 2 weeks after weaning

This study was conducted to determine the effects of low-protein diets supplemented with crystalline amino acids (AA) on performance and intestinal development in barrows (n = 32) over 2 weeks after weaning at 18 ± 1 day. Four maize-soybean meal based diets providing 0.93 g standardized ileal digestible lysine/MJ ME were prepared. The treatments were a control diet containing 23.1% CP (crude protein) and three low-protein diets (21.2, 18.9, and 17.2% CP, respectively), which were supplemented with crystalline AA to achieve an ideal AA pattern. Piglets were raised individually and had free access to feed and water. Average daily gain (ADG) and average daily feed intake (ADFI) were measured weekly. Severity of diarrhea was monitored twice per day. Blood from all piglets was taken for determining serum urea nitrogen on d 0, 7, and 14 and serum free AA concentration on d 14. At the end of the experiment, all piglets were killed to measure morphology of the small intestine and disaccharidase activities. Reducing CP level did not affect ADFI (P > 0.10) but resulted in poorer (linear, P < 0.05; quadratic, P < 0.05) ADG and feed:gain ratio (F:G) over the 2-week study period. However, most of the effect of dietary CP was due to the significant deterioration of performance with the 17.2% CP diet. Faecal consistency was improved linearly (P < 0.01) with dietary CP decrease. Reducing dietary CP from 23.1 to 17.2% resulted in a linear (P < 0.001) and quadratic (P < 0.001) decrease in serum urea nitrogen levels on d 7 and 14. Serum arginine (P < 0.001), glutamine (P < 0.05), and proline (P < 0.05) concentrations were decreased in pigs fed the 17.2% CP diet compared with those fed the control diet on d 14. Villous height was decreased (P < 0.05) in the duodenum and jejunum by the reduction of dietary CP. As dietary CP declined, lactase and sucrase activities were reduced (P < 0.01) in the proximal jejunum. In conclusion, reducing CP concentration from 23.1 to 17.2% led to decreased growth performance associated with morphological changes of the gut and reduced disaccharidase activities in the small intestine. But reducing dietary CP from 23.1 to 18.9% did not affect intestinal morphology and disaccharidase activities.     

Effect of feeding fermentable fiber on synthesis of total and mucosal protein in the intestine of the growing pig

In a previous study, a reduced efficiency of ileal digestible threonine (THR) use for body protein deposition was observed in growing pigs when pectin was included in the diet. This response was not due to increased physical endogenous ileal THR loss. Our aim was to explore the contribution of diet-induced increases in protein synthesis in the colon, especially mucins, to dietary THR requirements. Twelve barrows (21 kg mean BW) were fed either a cornstarch–soybean meal-based diet (Control) or Control with 12% pectin (Pectin). Pigs were given intravenously 1.5 mmol/kg BW of L-1-¹³C valine (40 mol%) to measure fractional and absolute synthesis rates (FSR, ASR, respectively) of mucosal and whole intestinal protein in the jejunum and colon. Dietary pectin inclusion increased plasma levels of glucose, isoleucine and glutamine (P < 0.05) but had no effect on insulin or urea nitrogen (P > 0.10). There were no differences in FSR and ASR of whole intestinal protein in jejunum and colon (P > 0.10). The FSR of mucosal proteins in colon, not in jejunum, was increased with dietary pectin supplementation (P < 0.05). Assuming mucosal protein mass is constant, these results imply that the higher protein synthesis in colon mucosa contributes to the reduced THR efficiency observed in pectin-supplemented diet.     

Dietary protein and fermentable carbohydrates contents influence growth performance and intestinal characteristics in newly weaned pigs

Increasing the dietary amount of fermentable carbohydrates (FC) may counteract the negative effects of protein fermentation in newly weaned piglets. To study this hypothesis, 272 newly weaned piglets were allotted to 4 dietary treatments in a 2 × 2 factorial arrangement with low and high FC (7.5 and 13.5%) and crude protein (CP, 15 and 22%) content as respective factors. Intestinal histology, enzyme activity, microbiota and fermentation products were determined in 8 pigs per treatment 7 days post-weaning.

In the 4 wk experimental period, interactions between dietary CP and FC content were found for feed intake (P = 0.022), daily gain (P = 0.001), and gain:feed (P = 0.033). The high-FC content reduced daily gain by 50 g/d in the low-CP diet, whereas the FC content did not affect growth performance in the high-CP diet. Over the 4 wk experimental period, daily gain (350 g/d) and feed intake (519 g/d) were highest for piglets on the low-CP low-FC diet. The high-FC content resulted in an increase in number of lactobacilli (P = 0.047) and a decrease of total coliforms (P = 0.06) in the small intestine. It increased the lactic acid content (P = 0.08) and reduced the ammonia content (P = 0.04) in the small intestine and increased the VFA content in the colon (P = 0.009). The reduction in CP content reduced ammonia concentration in the small intestine (P = 0.003). We concluded that dietary FC influenced microbial population and fermentation products in the gut. However, this was not reflected in an increased growth performance.     

Increasing diet viscosity using carboxymethylcellulose in weaned piglets stimulates protein digestibility

Ileal indigestible protein may be an important factor for the occurrence of post weaning diarrhoea in piglets. Depending on the quantity of indigested protein, an imbalance in the microbial community can occur, resulting in an overgrowth of pathogens. Diet viscosity may influence nutrient digestibility and substrate availability for microbial growth. Therefore, we examined the effect of dietary viscosity in piglet nutrition. Carboxymethylcellulose (CMC) was added as a model substance in order to increase diet viscosity. The effect of 1% supplemented CMC on nutrient digestibility, morphological and physiological parameters was measured in piglets 3 weeks post weaning at 26 days of age. The main effects of inclusion of CMC were:

– A 10% slower gastric emptying rate (P = 0.18).

– An increased protein hydrolysis in the gastric fraction, measured as increased nitrogen concentration in the liquid phase of gastric contents (26% in control vs. 34% in experimental group; P = 0.13).

– An increased production of the protein hydrolysing enzyme amino-peptidase from 359 U/g protein for the control diet to 516 U/g protein for the experimental diet (P < 0.01).

– A numerical increase in apparent ileal protein digestibility by 6% from 75.2% to 79.5% (P = 0.22) and a significant increase in faecal protein digestibility by 5% (P = 0.044).

These results indicate that an optimized diet viscosity might be one factor exerting a beneficial influence on protein digestibility. We hypothesize that the effect of diet viscosity on gastric emptying rate is the major factor.     

The C bicarbonate dilution technique to determine energy expenditure in young bulls validated by indirect calorimetry

We explored the applicability of the ¹³C bicarbonate dilution technique for determination of energy expenditure (EE) in young bulls in comparison to whole body indirect calorimetry (IC). Twelve bulls of a F2 German Holstein x Charolais cross (4.5 months, 332 ± 16 kg BM) received a diet providing 1000 kJ ME d^− 1 kg BM^− 0.75 and 4.3 g crude protein d^− 1 kg BM^− 0.75. Bulls were housed in respiration chambers and received an intravenous bolus of NaH¹³CO₃ (A: 3 μmol kg BM^− 1 (n = 2), B: 7 μmol kg BM^− 1 (n = 4), C: 17.5 μmol kg BM^− 1 (n = 6), 99 at.% ¹³C) into the jugular vein to measure EE. Simultaneously, EE was determined by IC. After the ¹³C administration blood samples and breath gas were collected from the animals in the respiration chamber during a 24-h period (7.00–7.00 h). The recovery of ¹³C in breath CO₂ (% of ¹³C dose) was irrespective of NaH¹³CO₃ dose (A: 69.7 ± 2.7%, B: 70.5 ± 4.5%, C: 75.0 ± 4.9%; P > 0.05). Only small amounts of ¹³C were excreted in urine (3.4 ± 2.6%) and feces (2.0 ± 1.3%). The EE determined by the ¹³C bicarbonate method using breath and blood ¹³C recovery rates as correction factors was not different from that measured by IC (816 ± 81 [blood] or 827 ± 101 [breath] vs. 820 ± 90 kJ d^− 1 kg BM^− 0.75). Bland–Altman analysis showed a 95% confidence interval for EE of ± 99 and ± 109 kJ d^− 1 kg BM^− 0.75 based on blood and breath ¹³C recovery, respectively. In conclusion, the ¹³C bicarbonate dilution method is appropriate to obtain reliable estimates of EE in young bulls using blood CO₂ or breath CO₂ under standardized experimental conditions, i.e. in the fasting state.     

A diet moderately deficient in zinc induces limited intestinal alterations in weaned pigs

The aim of this work was to test the hypothesis that a moderate zinc deficiency induces intestinal alterations in weaned piglets. A diet based on maize and soybean meal was formulated without supplemental zinc (33 ppm, zinc-deficient) or with added zinc (113 ppm, control). These diets were pair-fed for 18 or 27 d to intra-litter pairs of piglets weaned at 21 d of age. The feed intake and growth, plasma concentrations of zinc and alkaline phosphatase (ALP) activity, and morphometry, enzyme activities and the microflora of the mid-jejunum were investigated. Feed intake and growth were similar between diets and diarrhoea was not observed. By contrast, plasma zinc and ALP activity were much lower in zinc-deficient piglets at slaughter (P < 0.001). The weight of organs was unaffected, except colonic tissue that was lighter in piglets fed the zinc-deficient diet (P < 0.05). Neither villus-crypt intestinal architecture nor mucosal enzyme activities were altered. Jejunal counts of lactic acid bacteria and coliforms tended to be higher in the zinc-deficient pigs (P ≤ 0.10). In conclusion, feeding a diet moderately deficient in zinc for 18–27 d induced limited intestinal alterations in weaned pigs.     

The effect of dietary crude protein concentration and inulin supplementation on nitrogen excretion and intestinal microflora from finisher pigs

A 2 × 2 factorial experiment was used to investigate the interaction between dietary crude protein (CP) concentration (200 vs 140 g/kg) and inulin supplementation (0 vs 12.5 g/kg) on nitrogen (N) excretion and intestinal microflora from 16 boars (n = 4, 74.0 kg live weight). The diets were formulated to contain similar concentrations of digestible energy and lysine. Pigs offered the high CP diets had a higher excretion of urinary N (P < 0.01), faecal N (P < 0.01) and total N (P < 0.001) than the pigs offered the low CP diets. Inulin supplementation increased faecal N excretion (P < 0.05) and decreased urine: faeces N ratio (P < 0.05) compared to the inulin free diets. There was no significant effect (P > 0.05) of dietary treatment on N retention. There was an interaction (P < 0.05) between dietary CP concentration and inulin supplementation on caecal E.coli. Pigs offered the diet containing 200 g/kg CP plus inulin decreased the population of E.coli compared to the inulin supplemented 140 g/kg protein diet. However, CP concentration had no significant effect on the population of E.coli in the unsupplemented diets. Inulin supplementation increased caecal bifidobacteria (P < 0.01) compared to the inulin free diets. In conclusion, inulin supplementation favourably altered N excretion and lowered the population of E.coli at high CP concentrations.     

Effects of pre- and postnatal exposure to garlic and aniseed flavour on pre- and postweaning feed intake in pigs

The low nutrient intake shortly after weaning is a major cause of post-weaning problems. Feed intake after weaning is strongly related to feed intake during lactation. Feed intake during lactation, however, varies considerably between litters. We hypothesised that prenatal and postnatal exposure to certain flavours would increase the intake of feed containing the same flavours pre- and postweaning. Multiparous sows did (n = 17) or did not (n = 14) receive 50 g garlic granulate/powder and 25 g aniseed as daily additive to their diet during the last month of gestation and during lactation. From day 14 of lactation, litters were submitted to intermittent suckling: 12 h separation form the sow each day. During lactation, all litters had 40 g garlic and 20 g aniseed per kg added to their creep feed. After weaning, half of the litters had no additive in their diet. Piglets were weaned at 4 weeks (13 litters) or at 6 weeks (18 litters). At 6 weeks of lactation, litters of which the dam received the flavour in her diet, had a higher feed intake (309 ± 43 vs 233 ± 35 g/p/d) than litters of dams without the flavour, although the difference was not significant. Sow diet had no effect on postweaning feed intake, but postweaning piglet diet did. Late (week 6) weaned litters receiving the flavoured feed had a higher feed intake from 3 to 10 days after weaning (833 ± 38 vs 687 ± 58 g/p/d). Weight gain during the first 10 days after weaning was not affected by sow or pig diets. Feed intake and weight gain shortly after weaning were strongly related to feed intake during lactation (overall R = 0.64, P < 0.05 and R = 0.77, P < 0.05). We conclude that early experience with flavours increases later acceptance and improves adaptation to post weaning conditions.     

Effects of Chinese herbal ultra-fine powder as a dietary additive on growth performance, serum metabolites and intestinal health in early-weaned piglets

This study was conducted to determine the effects of dietary supplementation with a Chinese herbal ultra-fine powder on growth performance, serum metabolites and intestinal health in early-weaned piglets. Sixty piglets weaned at 21 days of age were randomly assigned to one of the 3 treatment groups, representing supplementation with 0 or 2 g/kg of the powder, or 0.2 g/kg of colistin to maize- and soybean meal-based diets (n = 20 per group). Dietary supplementation with the powder increased ADFI and ADG, improved the gain/feed ratio, and reduced the incidence of diarrhea in the weaned piglets (P < 0.05), compared with the non-additive group. In contrast to colistin, the Chinese herbs decreased (P < 0.05) serum levels of triglycerides and glucose and increased (P < 0.05) serum concentrations of ferrum and phosphorus. Collectively, these findings indicate that the Chinese herbal powder is safe and effective in preventing the weaning-associated intestinal dysfunction and improving the growth performance in piglets.     

The correlation between passage rate of digesta and dry matter digestibility in various stages of swine

The relationship between passage rate of digesta (PRD) and apparent faecal dry matter digestibility (DMD) was investigated in five trials. In trial 1, 2, and 3, 36 weanling (16.9 ± 3.0 kg), 24 growing (51.3 ± 8.8 kg), and 23 finishing (104.8 ± 5.2 kg) barrows were housed in metabolic crates. The beginning and end of 5-day collection periods were marked by the addition of 0.5% indigo carmine to the feed for total faeces collection and PRD determination by observing the time required for the marker to appear. In trial 4 and 5, 21 gestating gilts (215.0 ± 15.0 kg), and 19 lactating sows were individually penned. Addition of 0.5% chromic oxide to the feed enabled indirect determination of DMD and PRD. The PRD, which ranged from 12 to 80 h, was positively correlated with DMD in weanling (R² = 0.483, P < 0.001), growing (R² = 0.425, P < 0.01), and finishing (R² = 0.553, P < 0.001) pigs. Body weight and DMD were not significantly correlated in weanling (R² = 0.001, P = 0.893), growing (R² = 0.000, P = 0.995), or finishing (R² = 0.092, P = 0.156) pigs. A positive correlation between PRD, which ranged from 27 to 102 h, and DMD occurred in gestating gilts (R² = 0.231, P < 0.05), but not in lactating sows (R² = 0.014, P = 0.633). The results indicate that longer retention times of digesta improve DMD in swine. Also the results indicate the importance of PRD as a potential independent variable in digestibility assessments.     

Stimulation of the exocrine pancreas via a third CCK-receptor subtype?

The physiological role of the cholecystokinin1 receptor (CCK1R) and the cholecystokinin/gastrin receptor (CCK2R) in the enzyme release from the exocrine pancreas in various mammal species has been debated. Experiments in pigs have indicated that physiological levels of cholecystokinin-33 (CCK-33) elicit pancreatic enzyme release via CCK2Rs located in the gastro-duodenal region. Since gastrin and CCK have similar affinity for the CCK2R, the aim was to examine if gastrin can elicit a similar enzyme response as CCK, after infusion via the gastric artery. Weaned pigs were anaesthetised and surgically prepared with appropriate catheters. Pentagastrin (n = 6) or CCK-33 (n = 6), 13 pmol/kg, was infused via the gastric artery into the gastro-duodenal region and 20 min. later 130 pmol/kg of the same hormone was infused via the jugular vein to the general circulation. Pancreatic juice was collected in intervals after each infusion and analysed for its protein and enzyme (trypsin) content. CCK-33 gave rise to significantly higher protein and trypsin output compared to pentagastrin for both doses and infusion routes. The results indicate that low doses of CCK-33 infused to the duodenal region do not stimulate the exocrine pancreas via the CCK2R since the result can't be reproduced with pentagastrin. Since previous studies have indicated that CCK1R is not involved the present results indicate that a third CCK-receptor subtype might be involved in the stimulation of the exocrine pancreas.     

Intermittent suckling improves post-weaning feed uptake but does not change functional gut characteristics of piglets

Suckling pigs were separated from their dam for 24 h on day 21 (1 × 24 h fasting, n = 10) or day 21 and 24 (2 × 24 h fasting, n = 10). Pigs in the control group (n = 10) were not fasted before weaning. All pigs were weaned on day 28 postpartum. Feed intake during the first 4 days post-weaning was higher (P < 0.05) for pigs exposed to 1 × 24 h fasting compared with controls. Water consumption was not affected by fasting prior to weaning. The difference in post-weaning feed uptake was not reflected in any clinical traits, intestinal morphology, or activity of digestive enzymes (maltase, dipeptidylpeptidase IV, aminopeptidases A and N; P > 0.15). In conclusion, a short period of fasting prior to weaning can increase post-weaning feed uptake, although this had no clinical impact under the present experimental conditions.     

Effect of adding Lactobacillus plantarum or a formic acid containing-product to fermented liquid feed on gastrointestinal ecology and growth performance of piglets

A study was carried out to investigate whether adding a starter culture or a formic acid containing-product to fermented liquid feed of suboptimal microbial quality could improve the characteristics of the mixture and the gastrointestinal ecology and growth performance of piglets. Four experimental diets were prepared: Feed and water were mixed in the ratio 1:2.5 (w/w) in four closed tanks. Diet 1) Three times daily, 50% of the mixture stored in the tank was removed and then replaced with an equal amount of fresh feed and water, (FLF), positive control; Diet 2) Three times daily, 95% of the mixture stored in the tank was removed and then replaced with an equal amount of fresh feed and water. Escherichia coli K12 (1 × 10⁶/g) was added every morning (COLI); Diet 3) as the COLI treatment and added Lactobacillus plantarum VTT E-78076 (1 × 10⁶/g) every morning (+PLANTARUM); and Diet 4) as the COLI treatment and added 0.26 g AIV/KemiSile 2 plus/100 g mixture three times daily (+ACID). One hundred and sixty weaners were used. On day 14, one littermate from each pen was killed and the gastrointestinal tract removed. The remaining piglets were used to measure the effect of the experimental diets on growth performance during the first six weeks post-weaning. The +ACID diet had lower numbers of lactic acid bacteria and Enterobacteriaceae, higher numbers of yeasts, and lower concentration of lactic acid and acetic acid than the COLI and +PLANTARUM diets. Feeding the +PLANTARUM and the +ACID diets increased daily weight gain during the six weeks post-weaning (P ≤ 0.02) compared to feeding the COLI diet. The +ACID group showed the highest numerical daily feed intake in all periods. The gain/feed during the six weeks post-weaning tended to be lowest in the COLI group (P < 0.10). The counts of lactic acid bacteria able to grow at 20 °C were lowest in the stomach (P ≤ 0.003) and distal small intestine (P ≤ 0.06) of the +ACID group. The counts of yeasts able to grow at 37 °C in the stomach were highest in the +ACID (P ≤ 0.01) and FLF groups (P ≤ 0.09). The number of yeasts able to grow at 20 °C in the stomach and distal small intestine was highest in the FLF fed piglets, followed by the +ACID group. This study showed that addition of L. plantarum VTT E-78076 or AIV/KemiSile 2 plus to fermented liquid feed of suboptimal microbial quality improved growth performance without affecting the gastrointestinal ecology of piglets substantially.     

Physiological aspects and ileal gene expression profile of early-weaned piglets fed a low threonine diet

High dietary threonine extraction by the digestive tract suggests that threonine contributes to maintain gut physiology. The aims of this study were to investigate both the physiological disturbances and the molecular events caused by an inadequate dietary threonine supply to the ileum of piglets. We compared paracellular permeability and gene expression, using porcine cDNA microarrays, of the ileum of piglets weaned at 7 days of age fed either a low (LT; n = 7) or a control (C; n = 7) well balanced threonine diet for 2 weeks. At slaughter, the ileal paracellular permeability, measured by FD4 flux in Ussing chambers, increased in piglets fed a LT diet compared with C piglets (P = 0.017). Furthermore, 170 genes had their expression significantly modified in the ileum of the LT piglets: 64 were down regulated and 106 were up regulated. These genes are involved in immune response, apoptosis, energy metabolism, cell migration, epithelial permeability, RNA processing or protein translation. In conclusion, dietary threonine deficiency induced alteration of the ileal barrier and the ileum seems to respond by increasing its metabolic activity.     

The effect of administration of 2-iminobiotin at birth on growth rates, morbidity and mortality in piglets under farm conditions

It has since long been demonstrated that perinatal asphyxia in pigs can result in perinatal mortality, decreased viability/vitality at birth and reduced survival rates until 10 days of age. In human perinatology much interest is presently focussed on strategies to prevent adverse outcome arising from birth asphyxia. Given the rather high perinatal and postnatal losses in the pig industry, it is very interesting to explore rescue strategies to reduce adverse effects of postischemic organ damage caused by perinatal asphyxia also in newborn piglets.

The aim of this study was to determine the effects of postnatal treatment of piglets with 2-IminoBiotin (2-IB), a selective inhibitor of neuronal and inducible NitricOxideSynthase (nNOS and iNOS), under farm conditions on postnatal growth rates, morbidity and mortality.

In total 81 piglets from 15 litters were used. Immediately after birth, blood was collected from the umbilical artery and piglets were alternately assigned to either a control (saline) or drug (2-IB; 0.18 mg/kg bodyweight every 4 h during 24 h) group. Administration of control or drug started with an intravenous injection in the umbilical vein immediately after birth, followed by 6 intraperitoneal injections at 4 h intervals, starting 4 h after the intravenous injection. Piglets were checked for growth, morbidity and mortality until the experiment was finished (average age: 44 days).

Postnatal treatment with 2-IB resulted in significantly increased growth rates at 10 days of age (P = 0.02) (165 g/day compared to 140 g/day in controls), independently of health status and birth weight. At weaning 2-IB treated piglets tended to show higher growth rates (P = 0.06). Growth rates at the end of the experiment, morbidity and mortality were not affected by treatment.

It is hypothesized that 2-IB reduces the rather limited, nearly ‘physiological’ harmful effects occurring in the gastrointestinal tract, resulting from a short period of hypoxia-ischemia experienced during birth. This might explain the significantly increased growth rates at 10 days of life in 2-IB treated piglets. Selective inhibition of nNOS and iNOS might also result in increased availability of l-arginine for protein synthesis in newborns resulting in higher postnatal growth rates. However these issues need further investigations.

In conclusion, this study showed a positive effect of immediate postpartum administration of 2-IB during the first day after birth on growth rates up to 10 days of age. Furthermore, no negative effects of 2-IB treatment on piglet health and survival were found.     

Nitrogen balance in barrows fed low-protein diets supplemented with essential amino acids

This study was conducted to determine the effect of addition of essential amino acids (EAA) to low-protein diets on N balance in barrows. Thirty barrows (Duroc × Yorkshire) with an initial BW of 36 kg were fed 5 corn- and soybean meal-based diets containing 13.6 to 18.2% crude protein (CP) for 10 d in a randomized complete block design. The 18.2% CP diet was formulated without addition of EAA (Lys, Met or Thr). The other diets contained 13.6 to 16.5% CP and were supplemented with EAA to provide 0.83% true digestible lysine equal to that in the 18.2% CP diet. Fecal, urinary, and total N excretion as well as N retention (g/d) decreased with decreasing dietary CP level (P < 0.01). The apparent digestibility of N was almost the same for the 18.2 and 16.5 CP diets, but the value was 2% higher (P = 0.07) than that for the 13.6% CP diet. These findings indicate that, compared with the 18.2% CP diets, supplementation with three EAA to the lowest-protein diets (13.6 CP) is inadequate for maximum intestinal protein digestion, amino acid absorption, or tissue protein deposition in growing barrows.     

Association between butyrate and short-chain fatty acid concentrations in gut contents and faeces in weaning piglets

The concentration and composition of short-chain fatty acids (SCFA) in gastrointestinal and faecal samples were studied in weaning pigs fed different amounts and composition dietary fibre (DF). In Trial 1 a total of 50 castrated piglets were fed five experimental diets with varying contents of citrus pectin (soluble fibre) and barley hulls (insoluble fibre) and gastrointestinal contents were collected at euthanasia 9 days after weaning. In Trial 2, 120 pair-wise penned piglets were allocated to the same experimental diets as in Trial 1 (24 piglets per treatment), and fresh faecal samples were collected 5 and 32 days after weaning.

There was no difference in the concentrations of SCFA caused by dietary treatments, but across treatments there was a correlation between concentration of SCFA and the proportion of butyrate. The correlation was lowest in the caecum (r² = 0.22, P = 0.0007) and highest in the distal colon (r² = 0.45, P = 0.0001). In faeces there was no relationship 5 days after weaning (r² = 0.004. P = 0.64) but a correlation of r² = 0.25 (P = 0.0001) 32 days after weaning. The results suggest that adaptive changes and differences between piglets in fermentative capacity immediately after weaning are associated not only with a higher concentration of SCFA but also a changed fermentation profile.