Determination of ileal endogenous nitrogen losses and true ileal nitrogen digestibility during non-steady-state conditions of the 15N-isotope dilution technique.

The aim was to determine ileal endogenous nitrogen losses (ENL) and true ileal N-digestibility (TD-N) under non-steady-state conditions of the 15N-isotope dilution technique (15N-IDT), using diets generating low and high ENL and compare results to those obtained under steady-state conditions. Twelve growing pigs (mean LW 22.4 kg) fitted with a post-valve T-caecum cannula were fed an enzyme-hydrolysed casein (EHC)-based diet or an EHC diet + 4% quebracho tannins (QT) and were labelled via continuous 15N-leucine i.v. infusion or twice daily oral 15N-leucine administration. Digesta were collected daily over three consecutive hours with blood plasma sampled on the four consecutive days after cessation of 15N-labelling. There was a significant effect of sampling day on the dilution factor. Endogenous N losses were significantly lower for the EHC than the EHC+QT diet (2.41 vs. 8.69 g/kg DMI), while no significant effect of sampling day was observed. The TD-N of the EHC+QT diet did not differ from the TD-N of the EHC diet (95.1 vs. 92.0%). A significant effect of sampling day was observed for TD-N with day 1 and 2, being higher than day 4. Non-steady-state conditions overestimated ENL by 25-28% as compared to 3 h collections in steady-state conditions, but the relative overestimation was similar for the EHC diet as for the EHC+QT diet. TD-N did not differ significantly compared to 12 h steady-state measurements, but comparison to 3 h steady-state measurements showed that non-steady-state conditions overestimated TD-N for the EHC+QT diet by 9%. However, on day 4 this overestimation disappeared. Using the 15N-IDT during non-steady-state conditions can provide valuable additional data on endogenous N losses and TD-N.

Pre-calving feeding of rumen-protected rice bran to multiparous dairy cows improves recovery of calcaemia after calving.

Dairy cows can have different degrees of hypocalcaemia around calving. Lowering dietary Ca availability before calving can prevent it. Rice bran, treated for lower rumen degradability of phytic acid can reduce dietary availability of Ca. During 3 periods of 3 weeks, 113 multiparous cows calved in a single close-up group, which was fed first a control diet, then 140 g/kg DM of rumen-protected rice bran, and at last the control diet again. Cows joined the group 3 weeks before expected calving date and left it at calving. Blood samples were taken weekly before parturition and 0, 6 and 12 h after calving, as well as 3 and 28 d in lactation. Serum was analysed for Ca, Mg, and P. Rice bran introduction produced a transient serum Ca decrease. Rice bran feeding reduced serum P and its withdrawal reduced serum Mg. Serum Ca at calving, nadir of serum Ca and serum Ca the first 3 d after calving was higher in cows calving during rice bran feeding. Serum P decreased less and recovered faster after calving when cows had been fed rice bran. Rumen-protected rice bran reduced dietary availability of Ca and induced adaptation of Ca metabolism resulting in improved Ca and P homoeostasis at calving.

Large intestinal fermentation capacity of fattening pigs on organic farms as measured in vitro using contrasting substrates.

BACKGROUND: In accordance with the EU regulations, organic farms require pigs to be fed diets high in fibre, which may impact on the pigs' large intestinal fermentation capacity. The ability of pigs to ferment non-starch polysaccharides (NSP) depends on characteristics of the dietary NSP source and microbes present in the large intestine of pigs. Little information exists on the fibre fermentation capacity of organically raised pigs. The aim of this study was to determine the variation in fibre fermentation capacity of fattening pigs within and between organic farms using an in vitro batch culture method and three contrasting substrates: oligofructose, soy pectin and cellulose. RESULTS: Pigs from different organic farms showed varying fermentation capacities as assessed by gas production, kinetics and fermentation end-products formed (P < 0.01). Coefficients of variation between inocula within farms varied by up to 40% for gas production and kinetics, in particular for incubation with cellulose. No relationship between on-farm feeding practice and the pigs' fermentation capacity could be established. CONCLUSION: The fermentation capacity of pigs reared under organic conditions varies considerable between farms. Finishing pigs reared under organic farming conditions are fast fermenters of oligofructose and soy pectin. More than four donor animals should be used per inoculum to accurately assess in vitro fermentation capacity. Fermentation results could not be related to dietary management under on-farm conditions.

Repeated measurements of in vitro fermentation of fibre-rich substrates using large intestinal microbiota of sows.

BACKGROUND: Fibrous ingredients for pig diets can be characterized by in vitro fermentation. In vitro fermentation methods often use a one-time measurement of gas production during the incubation of test substrates with one faecal inoculum. The representativeness of this approach can be questioned as measuring time and number of animals from which inoculum originates may influence fermentation results. An in vitro fermentation trial was conducted incubating three fibrous substrates with three inocula in five replicates (different fermentation runs) to test the influence of run and origin of inocula. RESULTS: Total gas production and maximal rate of gas production differed (P < 0.05) between fermentation runs, but less than substrates (P < 0.01). The ranking order between substrates remained similar for each run. Fermentation of cellulose led to higher coefficients of variation between inocula compared to the fast fermentable substrates oligofructose and soy pectin. Differences ranged from 2% for total gas production up to 25% for maximal rate of gas production. CONCLUSION: One fermentation run can provide representative results for substrate ranking. Using multiple inocula mixed from four faecal samples each leads to high coefficients of variation for slow fermentable substrates like cellulose. Future studies should examine the optimal number of animals for inocula preparation to decrease variation.

Asynchronous supply of indispensable amino acids reduces protein deposition in milk-fed calves.

A balanced supply of indispensable amino acids (AA) is required for efficient protein synthesis. Different absorption kinetics (e.g., free vs. protein-bound AA) may, however, create asynchrony in postabsorptive availability of individual AA, thereby reducing the efficiency of protein deposition. We studied the effects of AA asynchrony on protein metabolism in growing, milk-fed calves. In 2 experiments, each with a change-over design including 8 calves, a milk replacer deficient in Lys and Thr was used. In Expt. 1, L-Lys and L-Thr were parenterally supplemented, either in synchrony (SYN), asynchrony (ASYN), or partial asynchrony (PART) with dietary AA. In Expt. 2, l-Lys and l-Thr were orally supplemented, either in SYN or ASYN with dietary AA. In Expt. 1, digested protein was used less efficiently for growth for ASYN (31.0%) than for SYN (37.7%), with PART being intermediate (36.0%). Indicator AA oxidation tended (P = 0.06) to be higher for ASYN. In Expt. 2, the efficiency of protein utilization was lower for ASYN (34.9%) than for SYN (46.6%). Calves spared AA from oxidation when the limiting AA were provided in excess after a short period (<24 h) of deprivation. Restoring AA balance by parenteral supplementation resulted in a 19% lower efficiency of digestible protein utilization than by oral supplementation, likely caused by splanchnic oxidation of imbalanced AA in excess to Thr. In conclusion, asynchronous availability of individual indispensable AA reduces the efficiency by which digested protein is retained in milk-fed calves. Furthermore, an AA imbalance in the splanchnic tissues may result in disproportionate AA oxidation.

Tolerance and safety evaluation of N,N-dimethylglycine, a naturally occurring organic compound, as a feed additive in broiler diets.

N,N-Dimethylglycine (DMG) is a tertiary amino acid that naturally occurs as an intermediate metabolite in choline-to-glycine metabolism. The objective of the present trial was to evaluate tolerance, safety and bioaccumulation of dietary DMG in broilers when supplemented at 1 g and 10 g Na-DMG/kg. A feeding trial was conducted using 480 1-d-old broiler chicks that were randomly allocated to twenty-four pens and fed one of three test diets added with 0, 1 or 10 g Na-DMG/kg during a 39 d growth period. Production performance was recorded to assess tolerance and efficacy of the supplement. At the end of the trial, toxicity was evaluated by means of haematology, plasma biochemistry and histopathology of liver, kidney and heart (n 12), whereas bioaccumulation was assessed on breast meat, liver, blood, kidney and adipose tissue (n 8). Carcass traits were similar between the control and 1 g Na-DMG/kg feed groups (P>0·05), but the feed:gain ratio was significantly improved at 1 g Na-DMG/kg feed compared with the control or the 10-fold dose (P=0·008). Histological examinations showed no pathological effects and results of haematology and plasma biochemistry revealed similar values between the test groups (P>0·05). Bioaccumulation occurred at the 10-fold dose, but the resulting DMG content in breast meat was comparable with, for instance, wheat bran and much lower than uncooked spinach. In conclusion, DMG at 1 g Na-DMG/kg improved the feed:gain ratio in broilers without DMG being accumulated in consumer parts. Furthermore, dietary supplementation with DMG up to 10 g Na-DMG/kg did not induce toxicity or impaired performance in broilers.

Intestinal barrier function and absorption in pigs after weaning: 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.

A novel model to explain dietary factors affecting hypocalcaemia in dairy cattle.

Most dairy cows exhibit different degrees of hypocalcaemia around calving because the gestational Ca requirements shift to the disproportionately high Ca requirements of lactation. Ca homeostasis is a robust system that effectively adapts to changes in Ca demand or supply. However, these adaptations often are not rapid enough to avoid hypocalcaemia. A delay in the reconfiguration of intestinal Ca absorption and bone resorption is probably the underlying cause of this transient hypocalcaemia. Several dietary factors that affect different aspects of Ca metabolism are known to reduce the incidence of milk fever. The present review describes the interactions between nutrition and Ca homeostasis using observations from cattle and extrapolations from other species and aims to quantitatively model the effects of the nutritional approaches that are used to induce dry cows into an early adaptation of Ca metabolism. The present model suggests that reducing dietary cation-anion difference (DCAD) increases Ca clearance from the blood by dietary induction of systemic acidosis, which results in hypercalciuria due to the loss of function of the renal Ca transient receptor potential vanilloid channel TRPV5. Alternatively, reducing the gastrointestinal availability of Ca by reducing dietary Ca or its nutritional availability will also induce the activation of Ca metabolism to compensate for basal blood Ca clearance. Our model of gastrointestinal Ca availability as well as blood Ca clearance in the transition dairy cow allowed us to conclude that the most common dietary strategies for milk fever prevention may have analogous modes of action that are based on the principle of metabolic adaptation before calving.

Intestinal gene expression in pigs: effects of reduced feed intake during weaning and potential impact of dietary components.

The weaning transition is characterised by morphological, histological and microbial changes, often leading to weaning-associated disorders. These intestinal changes can partly be ascribed to the lack of luminal nutrition arising from the reduced feed intake common in pigs after weaning. It is increasingly becoming clear that changes in the supply with enteral nutrients may have major impacts on intestinal gene expression. Furthermore, the major dietary constituents, i.e. carbohydrates, fatty acids and amino acids, participate in the regulation of intestinal gene expression. However, nutrients may also escape digestion by mammalian enzymes in the upper gastrointestinal tract. These nutrients can be used by the microflora, resulting in the production of bacterial metabolites, for example, SCFA, which may affect intestinal gene expression indirectly. The present review provides an insight on possible effects of reduced feed intake on intestinal gene expression, as it may occur post-weaning. Detailed knowledge on effects of reduced feed intake on intestinal gene expression may help to understand weaning-associated intestinal dysfunctions and diseases. Examples are given of intestinal genes which may be altered in their expression due to supply with specific nutrients. In that way, gene expression could be modulated by dietary means, thereby acting as a potential therapeutic tool. This could be achieved, for example, by influencing genes coding for digestive or absorptive proteins, thus optimising digestive function and metabolism, but also with regard to immune response, or by influencing proliferative processes, thereby enhancing mucosal repair. This would be of special interest when designing a diet to overcome weaning-associated problems.

An attempt to define the sodium requirement of lactating dairy cows in a tropical environment.

BACKGROUND: Lactating dairy cattle in the tropics may require more sodium (Na) owing to the hot and humid climatic conditions. It is unknown whether the current recommendations on Na for lactating cows can be quantitatively used in tropical countries. This study attempted to define the Na requirement of lactating dairy cows under tropical conditions by measuring Na levels in saliva, milk and faeces. RESULTS: The concentrations of Na and potassium (K) in milk, faeces and serum were not affected by dietary treatments. The amount of Na absorbed by cows fed the basal (low-Na) diet containing 0.4 g Na kg(-1) dry matter (DM) was equal to the amount of Na lost in the milk, showing that these animals were fed an Na-deficient ration. This observation was corroborated by salivary Na and K levels, with the cows on the low-Na diet having salivary Na concentrations below 120 mmol L(-1) in combination with salivary K concentrations above 20 mmol L(-1) (P < 0.05). CONCLUSION: Consumption of a daily ration formulated to contain the current Na requirement set by the NRC appears to provide too much Na for lactating cows under tropical conditions. A tentative value of 1.2 g kg(-1) DM is proposed as the Na requirement for dairy cows under tropical conditions.

Efficiency of fat deposition from non-starch polysaccharides, starch and unsaturated fat in pigs.

The aim was to evaluate under protein-limiting conditions the effect of different supplemental energy sources: fermentable NSP (fNSP), digestible starch (dStarch) and digestible unsaturated fat (dUFA), on marginal efficiency of fat deposition and distribution. A further aim was to determine whether the extra fat deposition from different energy sources, and its distribution in the body, depends on feeding level. A total of fifty-eight individually housed pigs (48 (SD 4) kg) were used in a 3 x 2 factorial design study, with three energy sources (0.2 MJ digestible energy (DE)/kg(0.75) per d of fNSP, dStarch and dUFA added to a control diet) at two feeding levels. Ten pigs were slaughtered at 48 (SD 4) kg body weight and treatment pigs at 106 (SD 3) kg body weight. Bodies were dissected and the chemical composition of each body fraction was determined. The effect of energy sources on fat and protein deposition was expressed relative to the control treatments within both energy intake levels based on a total of thirty-two observations in six treatments, and these marginal differences were subsequently treated as dependent variables. Results showed that preferential deposition of the supplemental energy intake in various fat depots did not depend on the energy source, and the extra fat deposition was similar at each feeding level. The marginal energetic transformation (energy retention; ER) of fNSP, dStarch and dUFA for fat retention (ERfat:DE) was 44, 52 and 49 % (P>0.05), respectively. Feeding level affected fat distribution, but source of energy did not change the relative partitioning of fat deposition. The present results do not support values of energetic efficiencies currently used in net energy-based systems.

Effects of exercise on L-carnitine and lipid metabolism in African catfish (Clarias gariepinus) fed different dietary L-carnitine and lipid levels.

African catfish (Clarias gariepinus) were fed four isonitrogenous diets (34 % crude protein), each containing one of two lipid (100 or 180 g/kg) and two L-carnitine (15 or 1000 mg/kg) levels. After 81 d of feeding, thirty-two fish (body weight 32 g) from each dietary group were randomly selected, sixteen fish were induced to a 3-h swim (speed of 1.5 body length (BL)/s), while the other sixteen fish were kept under resting condition. Fish fed 1000 mg L-carnitine accumulated 3.5 and 5 times more L-carnitine in plasma and muscle, respectively, than fish fed the 15 mg L-carnitine. Muscle L-carnitine content was significantly lower in exercised fish than in rested fish. High dietary lipid level (fish oil) led to an increase in muscle n-3 PUFA content and a decrease in SFA and MUFA content. In liver, the increase in dietary lipid level resulted in an increased levels of both n-6 and n-3 PUFA. L-carnitine supplementation significantly decreased n-3 PUFA content. Exercise decreased n-3 PUFA in both muscle and liver. Plasma lactate and lactate dehydrogenase, normally associated with increased glycolytic processes, were positively correlated with exercise and inversely correlated with dietary L-carnitine level. L-carnitine supplementation reduced significantly the RQ from 0.72 to 0.63, and an interaction between dietary L-carnitine and lipid was observed (P < 0.03). Our results indicate that an increase in fatty acids (FA) intake may promote FA oxidation, and both carnitine and exercise might influence the regulation of FA oxidation selectivity.

Sainfoin (Onobrychis viciifolia) silage in dairy cow rations reduces ruminal biohydrogenation and increases transfer efficiencies of unsaturated fatty acids from feed to milk.

The effects of replacing grass silage by sainfoin silage in a total mixed ration (TMR) based diet on fatty acid (FA) reticular inflow and milk FA profile of dairy cows was investigated. The experiment followed a crossover design with 2 dietary treatments. The control diet consisted of grass silage, corn silage, concentrate and linseed. In the sainfoin diet, half of the grass silage was replaced by a sainfoin silage. Six rumen cannulated lactating multiparous dairy cows with a metabolic body weight of 132.5 ± 3.6 kg BW0.75, 214 ± 72 d in milk and an average milk production of 23.1 ± 2.8 kg/d were used in the experiment. Cows were paired based on parity and milk production. Within pairs, cows were randomly assigned to either the control diet or the sainfoin diet for 2 experimental periods (29 d per period). In each period, the first 21 d, cows were housed individually in tie-stalls for adaptation, then next 4 d cows were housed individually in climate-controlled respiration chambers to measure CH4. During the last 4 d, cows were housed individually in tie stalls to measure milk FA profile and determine FA reticular inflow using the reticular sampling technique with Cr-ethylenediaminetetraacetic acid disodium salt dihydrate (EDTA) and Yb-acetate used as digesta flow markers. Although the dietary C18:3n-3 intake was lower (P = 0.025) in the sainfoin diet group, the mono-unsaturated FA reticular inflow was greater (P = 0.042) in cows fed the sainfoin diet. The reticular inflow of trans-9, trans-12-C18:2 and cis-12, trans-10 C18:2 was greater (P ≤ 0.024) in the sainfoin diet group. The cows fed sainfoin diet had a lower (P ≤ 0.038) apparent ruminal biohydrogenation of cis-9-C18:1 and C18:3n-3, compared to the cows fed the control diet. The sainfoin diet group had greater (P ≤ 0.018) C18:3n-3 and cis-9, cis-12-C18:2 proportions in the milk FA profile compared to the control diet group. Transfer efficiencies from feed to milk of C18:2, C18:3n-3 and unsaturated FA were greater (P ≤ 0.0179) for the sainfoin diet. Based on the results, it could be concluded that replacing grass silage by sainfoin silage in dairy cow rations reduces ruminal C18:3n-3 biohydrogenation and improves milk FA profile.

Influence of dietary components on development of the microbiota in single-stomached species.

After birth, development of a normal microbial community occurs gradually, and is affected by factors such as the composition of the maternal gut microbiota, the environment, and the host genome. Diet also has a direct influence, both on composition and activity of this community. This influence begins with the milk, when specific components exert their growth-promoting effect on a beneficial microbiota, thereby suppressing potential pathogens. For example, breast-fed infants compared with formula-fed babies usually have a microbial community dominated by bifidobacteria. When solid food is introduced (weaning), dramatic changes in microbial composition occur, so pathogens can gain access to the disturbed gastrointestinal (GI) ecosystem. However, use of specific dietary components can alter the composition and activity of the microbiota positively. Of all dietary components, fermentable carbohydrates seem to be most promising in terms of promoting proliferation of beneficial bacterial species. Carbohydrate fermentation results in the production of SCFA which are known for their trophic and health-promoting effects. Fermentation of proteins, on the other hand, is often associated with growth of potential pathogens, and results in production of detrimental substances including NH3 and amines. In terms of the GI microbiota, lipids are often associated with the antimicrobial activity of medium-chain fatty acids and their derivatives. The present review aims to provide deeper insights into the composition and development of the neonatal GI microbiota, how this microbiota can be influenced by certain dietary components, and how this might ultimately lead to improvements in host health.

Odour from animal production facilities: its relationship to diet.

Though bad odour has always been associated with animal production, it did not attract much research attention until in many countries the odour production and emission from intensified animal production caused serious nuisance and was implicated in the health problems of individuals living near animal farms. Odour from pig production facilities is generated by the microbial conversion of feed in the large intestine of pigs and by the microbial conversion of pig excreta under anaerobic conditions and in manure stores. Assuming that primary odour-causing compounds arise from an excess of degradable protein and a lack of specific fermentable carbohydrates during microbial fermentation, the main dietary components that can be altered to reduce odour are protein and fermentable carbohydrates. In the present paper we aim to give an up-to-date review of studies on the relationship between diet composition and odour production, with the emphasis on protein and fermentable carbohydrates. We hypothesise how odour might be changed and/or reduced by altering the diet of pigs. Research so far has mainly focused on the single effects of different levels of crude protein and fermentable carbohydrates on odour production. However, also important for odour formation are the sources of protein and fermentable carbohydrates. In addition, it is not only the amount and source of these compounds that is important, but also the balance between them. On the basis of our review of the literature, we hypothesise that odour nuisance from pig production facilities might be reduced significantly if there is an optimum balance between protein and fermentable carbohydrates in the diet of pigs.

A functional polymeric immunoglobulin receptor in chicken (Gallus gallus) indicates ancient role of secretory IgA in mucosal immunity.

Animals are continuously threatened by pathogens entering the body through natural openings. Here we show that in chicken ( Gallus gallus ), secretory IgA (sIgA) protects the epithelia lining these natural cavities. A gene encoding a chicken polymeric Ig receptor ( GG-pIgR ), a key component of sIgA, was identified, and shown to be expressed in the liver, intestine and bursa of Fabricius. All motifs involved in pIgR function are present, with a highly conserved Ig-binding motif in the first Ig-like domain. Physical association of GG-pIgR with pIgA in bile and intestine demonstrates that this protein is a functional receptor. Thus, as shown for mammals, this receptor interacts with J-chain-containing polymeric IgA (pIgA) at the basolateral epithelial cell surface resulting in transcytosis and subsequent cleavage of the pIgR, releasing sIgA in the mucosal lumen. Interestingly, the extracellular portion of GG-pIgR protein comprises only four Ig-like domains, in contrast with the five domain structure found in mammalian pIgR genes. The second Ig-like domain of mammalian pIgR does not have an orthologous domain in the chicken gene. The presence of pIgR in chicken suggests that this gene has evolved before the divergence of birds and reptiles, indicating that secretory Igs may have a prominent role in first line defence in various non-mammalian species.

G protein activation in rat ponto-mesencephalic nuclei is enhanced by combined treatment with a mu opioid and an adenosine A1 receptor agonist.

STUDY OBJECTIVES: Opioids delivered to the pons inhibit REM sleep, whereas pontine administration of adenosine enhances REM sleep. In other brain areas opioids and adenosine interact to produce antinociception. Adenosine A1 receptors and mu opioid receptors each activate Gi/Go proteins. This study tested the hypothesis that combined treatment with the adenosine A1 receptor agonist SPA and the mu opioid agonist DAMGO would enhance G protein activation to a greater level than produced by either agonist alone. G protein activation was quantified in seven brainstem regions regulating sleep and nociception. This study also tested the hypothesis that G protein activation caused by SPA would be concentration dependent and blocked by the adenosine A1 receptor antagonist DPCPX. DESIGN: Activation of G proteins was assessed autoradiographically by agonist stimulation of [35S]GTPgammaS binding in slide-mounted sections of rat brainstem. G protein activation was quantified in nCi/g tissue for pontine reticular formation, dorsal raphe, ventrolateral and dorsomedial periaqueductal gray, and laterodorsal and pedunculopontine tegmental nuclei. SETTING: N/A. PATIENTS OR PARTICIPANTS: N/A. MEASUREMENTS AND RESULTS: Combined treatment with SPA and DAMGO caused a partially additive increase in G protein activation that was significantly (p<0.01) greater than G protein activation caused by either agonist alone. Treatment with SPA alone caused a concentration dependent (p<0.001) increase in [35S]GTPgammaS binding that was blocked by DPCPX. CONCLUSION: Agonist activation of adenosine A1 receptors stimulates G proteins in brainstem nuclei regulating sleep and nociception. In these same nuclei, G protein activation by combined treatment with DAMGO and SPA was partially additive, suggesting that mu opioid and adenosine A1 receptors activate some common G protein pools.

The impact of low concentrations of aflatoxin, deoxynivalenol or fumonisin in diets on growing pigs and poultry.

In the present review, the quantitative impact of dietary aflatoxin, deoxynivalenol (DON) and fumonisin concentrations on performance of pigs and broilers is evaluated, with special emphasis on low concentrations of these toxins. Also, responses in performance of pigs and broilers to these three toxins are related to their absorption and elimination kinetics. By applying simple linear regression, information from many literature sources is integrated and condensed into, for example, estimates of depression in rates of weight gain, relative to non-contaminated diets, with increasing toxin concentrations. It was estimated that with each mg/kg increase of aflatoxin in the diet, the growth rate would be depressed by 16 % for pigs and 5 % for broilers. For DON, with each mg/kg increase in the diet, the growth depression was estimated at about 8 % for pigs, while broilers showed no response to DON concentrations below 16 mg/kg. Fumonisin showed the lowest impact on growth performance; with each mg/kg increase, the depression in growth rate was estimated at 0.4 and 0.0 % for pigs and broilers, respectively. Dietary concentrations that cause a 5 % reduction in growth rate were estimated at 0.3 and 1.0 mg/kg for aflatoxin for pigs and broilers, respectively; 1.8 and 0.6 mg/kg for pure and naturally contaminated DON for pigs, respectively; 21 and 251 mg/kg for fumonisin for pigs and broilers, respectively.

In vitro fermentation of various carbohydrate-rich feed ingredients combined with chyme from pigs.

Increased carbohydrate fermentation, compared with protein fermentation, could benefit gut health. In two in vitro experiments, the effect of carbohydrate-rich feed ingredients on fermentation characteristics of ileal chyme from pigs was assessed, using the cumulative gas production technique. Ingredients of the first experiment included gums, inulins, pectins, transgalacto-oligosaccharides, lactose and xylan. In the second experiment, a gum, pectin and transgalacto-oligosaccharides were added at different starting weights, to determine their effects on fermentation characteristics of chyme, in relation to differences in the carbohydrate concentrations. In comparison to fermentation of chyme alone, added carbohydrates led to higher total gas production (p < 0.05), faster maximum rate of gas production (except for xylan) (p < 0.05), and a decreased branched-chain fatty acids to straight chain fatty acids ratio (BCR) (p < 0.05). In the second experiment, for all carbohydrate ingredients, the BCR decreased with increasing starting weights (p < 0.05). If these supplemented dietary carbohydrates were to reach the terminal ileum of the living animal, carbohydrate fermentation in the large intestine could be stimulated, which is known to have beneficial effects on host health.