Excess dietary Lys reduces feed intake, stimulates jejunal CCK secretion and alters essential and non‑essential blood AA profile in pigs

Background Commercial diets are frequently formulated to meet or exceed nutrient levels including those of lim-iting essential amino acids(AA)covering potential individual variations within the herd.However,the provision of dietary excess of AA,such as Lys,may lead to reduced appetite and growth in pigs.The mechanisms modulat-ing these responses have not been extensively investigated.This study evaluated the effect of Lys dietary excesses on performance and satiety biomarkers in post weaning pigs.Methods Twenty-four pigs aged 21 d and weighing 6.81±0.12kg(mean±SEM)were individually housed and offered 1 of 4 dietary treatments for 3weeks:a diet containing a standardized ileal digestible Lys reaching 100%(T0),120%(T1),150%(T2)or 200%(T3)of the NRC(2012)requirements.At the end of the experiment,blood samples from the cephalic vein of the T0 and T3 groups were obtained for AA analysis.In addition,primary intestinal cultures from T0 pigs were used,following their humane killing,to evaluate the effect of Lys on gut hormone secretion and AA sensors gene expression under ex vivo conditions.Results Feed intake was linearly reduced(P<0.001)and the weight gain to feed ratio reduced(P<0.10)with increased dietary levels of Lys during the third-and first-week post weaning,respectively.Cholecystokinin con-centration(P<0.05)and the metabotropic glutamate receptor 1 and the solute carrier family 7 member 2(P<0.10)gene expression was enhanced in proximal jejunum tissues incubated with Lys at 20mmol/L when compared to the control(Lys 0mmol/L).Plasma Lys and Glu(P<0.05)concentration increased in the T3 compared to T0 pigs.In contrast,plasma levels of His,Val,Thr,Leu(P<0.05)and Gln(P<0.10)were lower in T3 than T0 pigs.Conclusion The present results confirm that excess dietary Lys inhibits hunger in pigs.Moreover,the results provide evidence of pre-and post-absorptive mechanisms modulating these responses.Lys dietary excesses should be nar-rowed,when possible,to avoid negative effects of the AA on appetite in pigs.

Susceptibility of dairy cows to subacute ruminal acidosis is reflected in both prepartum and postpartum bacteria as well as odd-and branched-chain fatty acids in feces

Background:The transition period is a challenging period for high-producing dairy cattle.Cows in early lactation are considered as a group at risk of subacute ruminal acidosis(SARA).Variability in SARA susceptibility in early lactation is hypothesized to be reflected in fecal characteristics such as fecal pH,dry matter content,volatile and odd-and branched-chain fatty acids(VFA and OBCFA,respectively),as well as fecal microbiota.This was investigated with 38 periparturient dairy cows,which were classified into four groups differing in median and mean time of reticular pH below 6 as well as area under the curve of pH below 6.Furthermore,we investigated whether fecal differences were already obvious during a period prior to the SARA risk(prepartum).Results:Variation in reticular pH during a 3-week postpartum period was not associated with differences in fecal pH and VFA concentration.In the postpartum period,the copy number of fecal bacteria and methanogens of unsusceptible(UN)cows was higher than moderately susceptible(MS)or susceptible(SU)cows,while the genera Ruminococcus and Prevotellacea_UCG-001 were proportionally less abundant in UN compared with SU cows.Nevertheless,only a minor reduction was observed in iso-BCFA proportions in fecal fatty acids of SU cows,particularly iso-C15:0and iso-C16:0,compared with UN cows.Consistent with the bacterial changes postpartum,the lower abundance of Ruminococcus was already observed in the prepartum fecal bacterial communities of UN cows,whereas Lachnospiraceae_UCG-001 was increased.Nevertheless,no differences were observed in the prepartum fecal VFA or OBCFA profiles among the groups.Prepartum fecal bacterial communities of cows were clustered into two distinct clusters with 70%of the SU cows belonging to cluster 1,in which they represented 60%of the animals.Conclusions:Inter-animal variation in postpartum SARA susceptibility was reflected in post-and prepartum fecal bacterial communities.Differences in prepartum fecal bacterial communities could alert for susceptibility to develop SARA postpartum.Our results generated knowledge on the association between fecal bacteria and SARA development which could be further explored in a prevention strategy.

Changes of the glutathione redox system during the weaning transition in piglets, in relation to small intestinal morphology and barrier function

Background: Weaning is known to result in barrier dysfunction and villus atrophy in the immediate post-weaning phase, and the magnitude of these responses is hypothesized to correlate with changes in the glutathione(GSH)redox system. Therefore, these parameters were simultaneously measured throughout the weaning phase, in piglets differing in birth weight category and weaning age, as these pre-weaning factors are important determinants for the weaning transition. Low birth weight(LBW) and normal birth weight(NBW) littermates were assigned to one of three weaning treatments;i.e. weaning at 3 weeks of age(3 w), weaning at 4 weeks of age(4 w) and removal from the sow at 3 d of age and fed a milk replacer until weaning at 3 weeks of age(3 d3 w). For each of these treatments, six LBW and six NBW piglets were euthanized at 0, 2, 5, 12 or 28 d post-weaning piglets, adding up 180 piglets.Results: Weaning increased the glutathione peroxidase activity on d 5 post-weaning in plasma, and duodenal and jejunal mucosa. Small intestinal glutathione-S-transferase activity gradually increased until d 12 post-weaning, and this was combined with a progressive rise of mucosal GSH up till d 12 post-weaning. Oxidation of the GSH redox status(GSH/GSSG Eh) was only observed in the small intestinal mucosa of 3 d3 w weaned piglets at d 5 postweaning. These piglets also demonstrated increased fluorescein isothiocyanate dextran(FD4) and horseradish peroxidase fluxes in the duodenum and distal jejunum during the experiment, and specifically demonstrated increased FD4 fluxes at d 2 to d 5 post-weaning. On the other hand, profound villus atrophy was observed during the weaning transition for all weaning treatments. Finally, LBW and NBW piglets did not demonstrate notable differences in GSH redox status, small intestinal barrier function and histo-morphology throughout the experiment.Conclusion: Although moderate changes in the GSH redox system were observed upon weaning, the GSH redox status remained at a steady state level in 3 w and 4 w weaned piglets and was therefore not associated with weaning induced villus atrophy. Conversely, 3 d3 w weaned piglets demonstrated GSH redox imbalance in the small intestinal mucosa, and this co-occurred with a temporal malfunction of their intestinal barrier function.

Dietary resistant starch alleviates Escherichia coli-induced bone loss in meat ducks by promoting short-chain fatty acid production and inhibiting Malt1/NF-κB inflammasome activation

Background:Escherichia coli(E.coli)infection in humans and animals usually comes with gut dysbiosis,which is potential culprit to skeletal health,it is still unclear to whether diet interfered gut microbiome changes can be a protective strategy to bone loss development.Here,the effects of resistant starch from raw potato starch(RPS),a type of prebiotic,on E.coli-induced bone loss and gut microbial composition in meat ducks were evaluated.Results:The results showed that dietary 12%RPS treatment improved bone quality,depressed bone resorption,and attenuated the pro-inflammatory reaction in both ileum and bone marrow.Meanwhile,the 12%RPS diet also increased the abundance of Firmicutes in E.coli-treated birds,along with higher production of short-chain fatty acids(SCFAs)especially propionate and butyrate.Whereas addition ofβ-acid,an inhibitor of bacterial SCFAs production,to the drinking water of ducks fed 12%RPS diet significantly decreased SCFAs level in cecum content and eliminated RPS-induced tibial mass improvement.Further,treatment with MI-2 to abrogate mucosa-associated lymphoid tissue lymphoma translocation protein 1(Malt1)activity replicated the protective role of dietary 12%RPS in E.coli-induced bone loss including reduced the inhibition on nuclear factorκB(NF-κB)inflammasome activation,decreased bone resorption,and improved bone quality,which were correlated with comparable and higher regulatory T cells(Treg)frequency in MI-2 and 12%RPS group,respectively.Conclusions:These findings suggested that the diet with 12%RPS could alleviate E.coli-induced bone loss in meat ducks by changing the gut microbial composition and promoting concomitant SCFAs production,and consequently inhibiting Malt1/NF-κB inflammasome activation and Treg cells expansion.

Non-starch Polysaccharide Degrading Enzymes in Corn and Wheat-Based Broiler Diets： Dual Activity for Major Substrates

This study consolidates the efficacy of a non-starch polysaccharide （NSP）ase enzyme-concept in corn and wheat-based broiler diets. The NSP building blocks of corn, wheat and soybean meal （SBM, 44% protein） were studied first. Cereal NSP primarily consists of arabinose, xylose and glucose molecules that form arabinoxylan, β-glucan and cellulose polysaccharides. In soybean meal （SBM）, glucose （cellulose） predominates, next to galactose and uronic acids that form “pectins”. Broiler performance progress using in-feed NSPase enzymes depends on the concentration, complexity and solubility of the substrate and the genetic potential of the animal, mainly. A dual NSPase enzyme-concept for cereal and SBM NSP, predominantly being arabinoxylan, β-glucan and cellulose, was developed. Methods for measuring enzyme activities （endo-1,4-β-xylanase （EC 3.2.1.8） and endo-1,3（4）-β-glucanase （EC 3.2.1.6）） were developed （AVEVE Biochem UNITS） and preparations thereof （XG） standardized to meet requirements for most challenging NSP （corn, barely soluble）. Feed intake （FI）, bodyweight gain （BWG） and feed：gain ratio （F：G） were assessed in three zootechnical studies, each using 160 Ross 308 broilers split in two feeding groups with 80 birds/group （10 replicates of eight） for 42 d （starter/grower period）. Respective corn-SBM, wheat-SBM and corn/wheat-SBM diets were used as negative control （NC） or added with the enzyme-concept （XG）. In the total period, XG ameliorated BWG and F：G compared to NC in each study, where BWG increased best in diets with corn and F：G lowered most in diets with wheat. The dual NSPase enzyme-concept offers ingredient flexibility in present setting by enhancing the nutritional content of corn, wheat and SBM, expectedly from cleaving major NSP target molecules. Thereby, broiler professionals increase feed formulation liberty and safety and production result simultaneously.

25-hydroxycholecalciferol reverses heat induced alterations in bone quality in finisher broilers associated with effects on intestinal integrity and inflammation

Background:Alterations in ambient temperature have been associated with multiple detrimental effects on broilers such as intestinal barrier disruption and dysbiosis resulting in systemic inflammation.Inflammation and 25-hydroxycholecalciferol(25-OH-D_(3))have shown to play a negative and positive role,respectively,in the regulation of bone mass.Hence the potential of 25-OH-D_(3)in alleviating heat induced bone alterations and its mechanisms was studied.Results:Heat stress(HS)directly induced a decrease in tibia material properties and bone mass,as demonstrated by lower mineral content,and HS caused a notable increase in intestinal permeability.Treatment with dietary 25-OH-D_(3)reversed the HS-induced bone loss and barrier leak.Broilers suffering from HS exhibited dysbiosis and increased expression of inflammatory cytokines in the ileum and bone marrow,as well as increased osteoclast number and activity.The changes were prevented by dietary 25-OH-D_(3)administration.Specifically,dietary 25-OH-D_(3)addition decreased abundance of B-and T-cells in blood,and the expression of inflammatory cytokines,especially TNF-α,in both the ileum and bone marrow,but did not alter the diversity and population or composition of major bacterial phyla.With regard to bone remodeling,dietary 25-OH-D_(3)supplementation was linked to a decrease in serum C-terminal cross-linked telopeptide of type I collagen reflecting bone resorption and a concomitant decrement in osteoclast-specific marker genes expression(e.g.cathepsin K),whereas it did not apparently change serum bone formation markers during HS.Conclusions:These data underscore the damage of HS to intestinal integrity and bone health,as well as that dietary 25-OH-D_(3)supplementation was identified as a potential therapy for preventing these adverse effects.

A comparative study to determine the effects of breed and feed restriction on glucose metabolism of chickens

The glucose metabolism of poultry draws wide attention as they have nearly twice the fasting blood glucose than that of mammals.To define the relationship between glucose metabolism and breed of chicken,the outcomes from different growth rate chickens showed that Arbor Acres(AA)broilers,a well-known fast-growing breed,had a lower fasting blood glucose concentration and glucose clearance rate when compared to Silky chickens,a Chinese traditional medicinal chicken with black skin and a slow growth rate.Moreover,AA broilers had a relatively slow rise in blood glucose in response to oral glucose solution than the Silky chickens on 21 and 42 d(P<0.05),which is probably attributed to downregulated expression of pancreatic insulin(INS),and upregulated transcription of phosphoenolpyruvate carboxy kinase 1(PCK1)and glucose transporter 2(GLUT2)in the liver of AA broilers(P<0.05).In response to feeding restriction from 7 to 21 d,both the fasting blood glucose and the response speed of AA broilers to oral glucose were increased on d 21(P<0.05),and the serum glucose concentrations after 3 weeks compensatory growth were improved by early feed restriction in AA broilers.Feed restriction could also upregulate the mRNA level of pancreatic INS on d 21 and 42,as well as decrease the expressions of PCK1,glucose-6-phosphatase catalytic(G6PC),and GLUT2 in the liver on d 21(P<0.05)when compared to the free feeding group.These results revealed that Silky chickens have a stronger capability to regulate glucose homeostasis than AA broilers,and feed restriction could improve the fasting blood glucose and the response to oral glucose of AA broilers.

Fermented calcium butyrate supplementation in post-peak laying hens improved ovarian function and tibia quality through the“gut-bone”axis

The compromised egg quality and leg abnormality during the end of the laying cycle(after 40 weeks)have been leading to poor animal welfare and substantial economic losses.Therefore,the effects of fermented calcium(Ca)butyrate,produced by fermentation by Clostridium butyricum,on production,eggshell quality,and tibial property of hens were explored.A total of 192 Hy-line brown laying hens at50-week-old were assigned to a basal diet or the basal diet with 300 mg/kg of the fermented Ca butyrate from 50 to 58 weeks of age.Each treatment had 6 replicates with 16 hens each.The diet supplemented with 300 mg/kg fermented Ca butyrate notably increased egg weight,ovarian follicle number,and eggshell strength(P=0.072)as compared to the basal diet,which were associated with cytokine secretion,toll-like receptor signaling pathways,and intestinal immunity based on the RNA-seq data from the granulosa.Dietary Ca butyrate inclusion decreased the expression of ileal tumor necrosis factor-alpha and serum pro-inflammatory cytokine concentration,as well as increased the content of serum immunoglobulin A when compared to the basal diet(both P<0.05).The birds that received fermented Ca butyrate diets exhibited higher villus height(P<0.05)and upregulated expression of tight junction proteins,whereas it did not alter the composition of cecal microbiota(P>0.05).In addition,the diet with fermented Ca butyrate reduced the number of osteoclasts in the proximal tibia and the level of C-terminal cross-linked telopeptide of type I collagen,a bone resorption marker(P<0.05),whereas it tended to increase the concentration of the procollagen type I N-terminal propeptide that reflects bone formation marker in serum.Moreover,the layers fed fermented Ca butyrate diets possessed higher(P<0.05)bone area and trabecular number of the proximal tibia,yield load,and ultimate load than those that consumed basal diets.Collectively,dietary fermented Ca butyrate supplementation in post-peak layer diets improved the ovarian function and tibia quality,which might be related to enhancing intestinal integrity and consequently decreasing inflammation mediated bone resorption.

Calcium supplementation in low nutrient density diet for meat ducksimproves breast meat tenderness associated with myocyte apoptosisand proteolytic changes

To define the relationship between dietary nutrient density, calcium (Ca), and meat quality in meatducks. A total of 288 male Cherry Valley SM3 medium ducklings were fed a common standard starter dietuntil d 14. At 15 d of age, ducks were randomly divided into 2 treatment groups and fed either a conventionaldiet or a low nutrient density (LND) diet. Compared with the conventional diet, the energy wasreduced in the LND diet by 8.6% and 16.8% in grower (15 to 35 d) and finisher (36 to 56 d) phases,respectively, while other essential nutrients were kept proportionate to energy. The LND diet decreasedthe shear force (P < 0.05) and increased the lightness values of the pectoralis muscle when compared tothe conventional diet, suggesting that LND diet exerted a beneficial role in meat quality. Subsequently,the effects of grated Ca in the LND diet on meat quality of pectoralis muscle were evaluated. A total of 576male ducklings were fed a common starter diet until d 14, followed by feeding 4 LND diets with 0.5%,0.7%, 0.9%, and 1.1% Ca. The results show that LND diets with 0.7% or more Ca decreased the shear force ofpectoralis major muscle in 42-d-old meat ducks (P < 0.05). To explore the mechanism underlying Ca andtenderness, data from birds fed either 0.5% or 1.1% Ca in the LND diet indicated that birds fed 1.1% Caexhibited lower shear force, upregulated calpains 1 expression, and higher calpains activity compared tothose fed the LND diet with 0.5% Ca (P < 0.05). Moreover, the 1.1% Ca LND diet induced a higher myocyteapoptosis (P =0.06) and upregulated mRNA expression of caspase-3 (P =0.07) in breast muscle. Our datasuggest that LND diets with 0.9% or 1.1% Ca had a positive role in the tenderness of breast meat,particularly the enhancing effect of 1.1% Ca LND diet on tenderness seems to be associated with proteolyticchanges of myofibrillar proteins and myocyte apoptosis in meat ducks.