Mycoplasmosis: cervical and uterine inoculation of heifers with a Danish strain of Mycoplasma bovigenitalium

The “Κ” strain of Mycoplasma bovigenitalium has proved to be pathogenic for the mammary gland of cows, for the genital tract of bulls, and for calves (Εrnø 1967, Blom & Εrnø 1967, Εrnø 1969). Antibodies can be demonstrated in the blood following infection of the mammary gland, and after intravenous and intraperitoneal inoculation of calves with or without clinical signs of infection.     

The migration test on circulating bovine leukocytes and its possible application in the diagnosis of Johne's disease

The leukocyte migration test for in vitro studies of delayed type hypersensitivity has recently been reviewed (Søborg & Ben-dixen 1967; Bendixen & Søborg 1969). Søborg & Bendixen applied the test to circulating leukocytes in man and thereby widely increased the potentialities of this test. They obtained high leukocyte yields with only moderate erythrocyte admixture by harvesting the supernatant plasma after sedimentation of the erythrocytes for 60 min. at 37°C in the normal gravitational field (1 × g)- Their procedure was unsuitable for the present investigation because bovine erythrocytes sediment so slowly. Sedimentation after clumping at the interphase of aqueous solutions of polymers, dextran and methylcellulose, in combination with metrizoic acid (Böyum 1968) was tried without success because the vast majority of the leukocytes sedimented together with the erythrocytes. Separation of leukocytes from erythrocytes could not be achieved by differential centrifugation.     

Rosette nanotubes inhibit bovine neutrophil chemotaxis

Migration of activated neutrophils that have prolonged lifespan into inflamed organs is an important component of host defense but also contributes to tissue damage and mortality. In this report, we used biologically-inspired RGD-tagged rosette nanotubes (RNT) to inhibit neutrophil chemotaxis. We hypothesize that RGD-RNT will block neutrophil migration through inhibition of MAPK. In this report, RNT conjugated to lysine (K–RNT) and arginine-glycine-aspartic acid-serine-lysine (RGDSK-RNT) were co-assembled in a molar ratio of 95/5. The effect of the resulting composite RNT (RGDSK/K–RNT) on neutrophil chemotaxis, cell signaling and apoptosis was then investigated. Exposure to RGDSK/K–RNT reduced bovine neutrophil migration when compared to the non-treated group (p < 0.001). Similar effect was seen following treatment with ERK1/2 or p38 MAPK inhibitors. Phosphorylation of the ERK1/2 and p38 MAPK was inhibited at 5 min by RGDSK/K–RNT (p < 0.05). The RGDSD/K-RNT did not affect the migration of neutrophils pre-treated with αvβ3 integrin antibody suggesting that both bind to the same receptor. RGDSK/K–RNT did not induce apoptosis in bovine neutrophils, which was suppressed by pre-exposing them to LPS (p < 0.001). We conclude that RGDSK/K–RNT inhibit phosphorylation of ERK1/2 and p38 MAPK and inhibit chemotaxis of bovine neutrophils.     

Mycoplasmosis: Demonstration of Pathogenicity of a Danish Strain of Mycoplasma

During the fall of 1966 several strains of Mycoplasma were isolated from semen samples of bulls. A strain “K” isolated from a bull with simultaneous occurrence of leucocytes and mycoplasmas in the semen was selected for a series of experiments; the mammary gland was chosen as pilot organ.     

Acute rhabdomyolysis ("tying-up") in standardbred horses. A morphological and biochemical study

LINDHOLM, A., H.-E. JOHANSSON & P. KJÆRSGAARD: Acute rhabdomyolysis (“tying-up”) in standardbred horses. A morphological and biochemical study. Acta vet. scand. 1974, 15, 325–339. — Morphological, biochemical and histochemical changes were studied in muscle needle biopsy specimens (gluteus medius) from 59 standardbred trotters with acute clinical symptoms of the “tying-up” disease. All horses had increased levels of serum enzymes SGOT and SCPK. The biopsy specimens were taken at various intervals after onset of clinical symptoms (1–4 hrs., 18–24 hrs. and 2–20 days). Ry light microscopy it was shown that the muscular alterations had a focal distribution and were of the hyalin degeneration type with insignificant inflammatory reaction and slight calcification. The ultrastructural changes apparently commenced with myofibrillar waving, mitochondrial and sarcotubular alterations and terminated with myofibrillar degeneration and necrosis with invasion of inflammatory cells. The inflammatory cells were ultrastructurally similar to monocytes and macrophages. The degenerative changes mainly comprised fast twitch (FT and FTH) fibres as histochemically evidenced by myofibrillar ATPase and alkaline phosphatase staining.Riopsies from diseased muscle 1–4 hrs. after the onset of “tyingup” contained a low muscle concentration of glycogen, ATP and CP and a high concentration of lactate and glucose. Hence it is suggested that the described muscular alterations may be caused by a deranged carbohydrate metabolism caused by a local hypoxia.It was found that the “tying-up” disease resembled idiopathic rhabdomyolysis in man and was thus designated “equine rhabdomyolysis”.histochemistry; horse; rhabdomyolysis; skeletal muscle; “tying-up”; ultrastructure.     

Pampas deer (Ozotoceros bezoarticus) courtship and mating behavior

Background

Pampas deer, Ozotoceros bezoarticus (Linnaeus 1758), is a South American grazing deer categorized as "near threatened". However, knowledge about pampas deer behavior including courtship and mating is scarce and incomplete. The aim of this study was to characterize the courtship and mating behavior of the pampas deer (Ozotoceros bezoarticus), an endangered species from South America.

Methods

We performed focal observations of 5 males allocated at the Estación de Cría de Fauna Autóctona Cerro Pan de Azúcar, Uruguay, 4 times a day from 5 to 20 minutes each time on a daily basis from February to May. During that period we recorded all courtship and mating behaviors, as well as quantified the frequency of the specific behaviors shown. As mating were rarely observed, we recorded that behavior when it was observed in the context of other studies performed in the same population during the following 2 years.

Results

During the observation period we recorded 928 courtships and 5 mating periods. In addition, we recorded 10 more matings performed during other studies, totaling 15. The duration of each mating calculated from the 15 recordings was 3.9 ± 0.4 s, and the total period of female receptivity (from first to last mating acceptance) was 8.2 ± 1.1 min. Main observed courtship behaviors in males were “chase” and “ostentation”, while the most observed close to mating were “chinning”, “raised head” and “anogenital sniffing”. The most observed behaviors in females during the mating period were “vulva exhibition” and “move away”.

Conclusion

This is the first detailed report in pampas deer mating behavior. Estrus lasted only 8 min accepting only 3 short copulations per estrus. However, female behavior during courtship can be characterized as highly proceptive.     

Source of fiber influences growth,immune responses,gut barrier function and microbiota in weaned piglets fed antibiotic-free diets

This study examined the impacts of different fiber sources on growth, immune status and gut health in weaned piglets fed antibiotic-free diets. Sixty piglets (BW = 8.18 ± 1.35 kg) were assigned to 3 dietary treatments based on BW and gender in a randomized complete block design (5 replicates/treatment and 4 piglets [2 barrows and 2 gilts]/replicate): (1) an antibiotic-free diet (control, CON); (2) CON + 6% wheat bran (WB); (3) CON + 4% sugar beet pulp (SBP). Dietary WB supplementation tended to increase ADG compared with CON from d 1 to 14 (P = 0.051) and from d 1 to 28 (P = 0.099). Supplementation of WB increased (P < 0.05) G:F compared with CON and SBP from d 1 to 14 and from d 1 to 28. Compared with CON, the addition of WB reduced (P < 0.05) diarrhea rate from d 1 to 14 and tended (P = 0.054) to reduce diarrhea rate from d 1 to 28. The addition of WB decreased (P < 0.05) serum diamine oxidase activity on d 14, and up-regulated (P < 0.05) ileal mRNA levels of occludin on d 28 when compared with CON. Piglets fed WB showed decreased (P < 0.05) serum interleukin-6 levels compared to those fed SBP and decreased (P < 0.05) ileal interleukin-8 levels compared to those fed CON and SBP on d 28. Supplementation of WB increased (P < 0.05) serum levels of immunoglobulin A (IgA), IgG and IgM compared with SBP on d 14, and increased (P < 0.05) the levels of serum IgA and ileal sIgA compared with CON and SBP on d 28. Piglets fed WB showed an enhanced (P < 0.05) α-diversity of cecal microbiota than those fed SBP, while piglets fed SBP showed reduced (P < 0.05) α-diversity of cecal microbiota than those fed CON. Compared with CON, the addition of WB elevated (P < 0.05) the abundance of Lachnospira and cecal butyric acid level. Piglets fed WB also showed increased (P < 0.05) abundances of Lachnospira and unclassified_f_Lachnospiraceae compared with those fed SBP. Collectively, the supplementation of WB to antibiotic-free diets improved performance, immune responses, gut barrier function and microbiota compared with the CON and SBP fed piglets. Therefore, supplementing weaned piglets with WB was more effective than SBP.     

Characterization and identification of caprine, genital mycoplasmas

A total of 55 mycoplasma strains, isolated from the vagina of goats, were examined. Three strains, being arginine positive and glucose negative, could not be finally classified. Five isolates were identified as Acholeplasma laidlawii. Fourty-seven strains were phosphatase positive, glucose and arginine negative. Nine of these formed “film and spots” on standard growth medium, and reduced tetrazolium aerobically. Serological examination identified 7 as M. agalactiae, while 2 were M. bovis. The remaining 38 isolates did not reduce tetrazolium aerobically, and did not produce “film and spots.” on standard growth medium. All these except one were identified as M. bovigenitalium by immunofluorescence. Their relationship to group 11 otf Al-Aubaidi is discussed.     

Multi-carbohydrase enzymes improve feed energy in broiler diets containing standard or low crude protein

This study evaluated the effect of multi-carbohydrase (MC) on energy and nitrogen (N) balance and gene expression in broilers fed diets with different crude protein (CP) contents. The study employed a 2 × 2 factorial arrangement of treatments. The factors were presence or absence of MC, and standard (SCP) or low (LCP) dietary CP concentration. A 3-phase feeding program was used, including starter (0 to 7 d), grower (8 to 17 d) and finisher (18 to 28 d) phases. The study was undertaken in closed calorimetry chambers. Each of the 4 dietary treatments was replicated 8 times in total across 2 runs, with 2 birds per replicate (n = 64). Data for energy partitioning and N balance were collected from d 25 to 28. On d 28, birds were euthanized to collect muscle and intestinal tissue samples for gene expression. The results showed that the MC increased apparent metabolizable energy (AME, P < 0.01) and net energy (NE, P < 0.05), and reduced the feed conversion ratio (FCR, P < 0.01) in all diets. The proportion of energy retained as fat per total energy retention (REf/RE) was positively correlated with feed AME and NE (r = 0.541, P < 0.01 and r = 0.665, P < 0.001, respectively), suggesting that feed energy augmented with increased fat gain. Muscle ATP synthase subunit alpha (ATP5A1W) gene expression had a positive correlation with REf/RE and feed NE (r = 0.587, P < 0.001 and r = 0.430, P < 0.05, respectively). Similarly, muscle peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PGC-1A) expression was negatively correlated with weight gain and positively correlated with FCR (r = −0.451, P < 0.05 and r = 0.359, P < 0.05, respectively). These correlations show that over-expressions of muscle genes related to energy production reduce bird performance. This study demonstrated that MC increase dietary energy utilization, regardless of dietary CP concentration. However, the energy released by the enzymes increases feed energy-to-CP ratio, meaning there is excess energy that is then deposited as body fat. This suggests that supplemental MC in broiler feeds is beneficial if diets are formulated to contain marginal energy levels.     

Perpetuation of Leishmania: some novel insight into elegant developmental programs

Leishmania spp. are polarized single-celled eukaryotic parasites, the perpetuation of which relies on two other organisms they “use” as hosts. One of the Leishmania host organisms is a blood-feeding female sand fly, the second host being a mammal that acts as a blood source for the female sand fly. Leishmania-hosting sand flies transmit the metacyclic promastigote developmental stage to the mammal skin. While many mammals are known to act as sand fly blood sources, only some of these mammals are/will be “used” as Leishmania hosts. This host status means that skin as well as skin-distant tissues and cell lineages (mononuclear phagocytes and fibroblasts) of these mammals are rapidly and continuously remodelled as niches where Leishmania will deploy its developmental programs: it is noteworthy that without the deployment of the developmental program underlying Leishmania transmission from the mammal to the blood-searching and blood-feeding sand flies, the perpetuation of Leishmania will be suspended. While post genomic approaches are providing insight about some features of Leishmania major, Leishmania infantum/chagasi and Leishmania braziliensis, such approaches are not yet available for the natural hosts (wild rodents, wild sand flies) these Leishmania species “use” as hosts.     

Changes in progenitors and differentiated epithelial cells of neonatal piglets

This study aimed to assess the changes of small intestinal morphology,progenitors,differentiated epithelial cells,and potential mechanisms in neonatal piglets.Hematoxylin and eosin staining of samples from 36 piglets suggested that dramatic changes were observed in the jejunum crypts depth and crypt fission index of neonatal piglets(P<0.001).The number of intestinal stem cells(ISC)tended to increase(P<0.10),and a decreased number of enteroendocrine cells appeared in the jejunal crypt on d 7(P<0.05).Furthermore,the mRNA expression of jejunal chromogranin A(ChgA)was down-regulated in d 7 piglets(P<0.05).There was an up-regulation of the adult ISC marker gene of SPARC related modular calcium binding 2(Smoc2),and Wnt/b-catenin target genes on d 7(P<0.05).These results were further verified in vitro enteroid culture experiments.A mass of hollow spheroids was cultured from the fetal intestine of 0-d-old piglets(P<0.001),whereas substantial organoids with budding and branching structures were cultured from the intestine of 7-d-old piglets(P<0.001).The difference was reflected by the organoid budding efficiency,crypt domains per organoid,and the surface area of the organoid.Furthermore,spheroids on d 0 had more Ki67-positive cells and enteroendocrine cells(P<0.05)and showed a decreasing trend in the ISC and goblet cells(P<0.10).Moreover,the mRNA expression of spheroids differed markedly from that of organoids,with low expression of intestinal differentiation gene(Lysozyme;P<0.05),epithelial-specific markers(Villin,E-cadherin;P<0.05),and adult ISC markers(leucine-rich repeat-containing G protein-coupled receptor 5[Lgr5],Smoc2;P<0.001),and upregulation of fetal marker(connexin 43[Cnx43];P<0.05).The mRNA expression of relevant genes was up-regulated,and involved in Wnt/b-catenin,epidermal growth factor(EGF),Notch,and bone morphogenetic protein(BMP)signaling on d 7 organoids(P<0.05).Spheroids displayed low differentiated phenotype and high proliferation,while organoids exhibited strong differentiation potential.These results indicated that the conversion from the fetal progenitors(spheroids)to adult ISC(normal organoids)might largely be responsible for the fast development of intestinal epithelial cells in neonatal piglets.     

Serum biochemical parameters and amino acids metabolism are altered in piglets by early-weaning and proline and putrescine supplementations

The study was to investigate the effect of early-weaning stress and proline (Pro) and putrescine (Put) supplementations on serum biochemical parameters and amino acids (AA) metabolism in suckling and post-weaning pigs. Blood and small intestinal mucosa were harvested from suckling piglets at 1, 7, 14, and 21 d of age and piglets on d 1, 3, 5, and 7 after weaning at 14 d of age, as well as from piglets received oral administration of Pro and Put from 1 to 14 d old. In suckling piglets, the serum glucose, albumin and total cholesterol levels were increased (P < 0.05) with increasing age, whereas the serum globulin, urea nitrogen (BUN), alkaline phosphatase (ALP) and aspartate aminotransferase (AST) levels were lowered (P < 0.05). The concentrations of most serum AA and the AA transporters related gene expressions were highest in 7-d-old piglets (P < 0.05), whereas the phosphorylation status of the mammalian target of the rapamycin (mTOR) signaling pathway in the small intestine increased in piglets from 1 to 21 d old (P < 0.05). Weaning at 14 d old increased (P < 0.05) the BUN and triglycerides levels in serum, as well as jejunal solute carrier family 7 member 6 (SLC7A6), ileal SLC36A1 and SLC1A1 mRNA abundances at d 1 or 3 post-weaning. Weaning also inhibited (P < 0.05) the phosphorylation levels of mTOR and its downstream ribosomal protein S6 kinase 1 (S6K1) and 4E-binding protein-1 (4EBP1) in the small intestine of weanling pigs. Oral administration of Put and Pro decreased (P < 0.05) serum ALP levels and increased (P < 0.05) intestinal SLC36A1 and SLC1A1 mRNA abundances and mTOR pathway phosphorylation levels in post-weaning pigs. Pro but not Put treatment enhanced (P < 0.05) serum Pro, arginine (Arg) and glutamine (Gln) concentrations of weaning-pigs. These findings indicated that early-weaning dramatically altered the biochemical blood metabolites, AA profile and intestinal mTOR pathway activity, and Pro and Put supplementations improved the AA metabolism and transportation as well as activated the intestinal mTOR pathway in weanling-pigs. Our study has an important implication for the broad application of Pro and Put in the weaning transition of piglets.     

Different dietary protein sources influence growth performance,antioxidant capacity,immunity,fecal microbiota and metabolites in weaned piglets

The inclusion of high-quality proteins are commonly used in swine production.Our research investigated the effects of hydrolyzed wheat protein(HWP),fermented soybean meal(FSBM),and enzyme-treated soybean meal(ESBM)on growth performance,antioxidant capacity,immunity,fecal microbiota and metabolites of weaned piglets.A total of 144 piglets(weaned at 28 d)were allotted to 3 dietary treatments with 6 replicate pens per treatment and 8 piglets per pen.This study included 2 periods:d 0 to14 for phase 1 and d 15 to 28 for phase 2.Dietary treatments contained 15.90%HWP,15.80%FSBM,and 15.10%ESBM in phase 1,and 7.90%HWP,7.80%FSBM,and 7.50%ESBM in phase 2,respectively.The ADG of piglets in ESBM was increased(P<0.05)compared with HWP and FSBM during d 1e28.Compared with HWP and FSBM,ESBM increased(P<0.05)the ferric reducing ability of plasma(FRAP),and the serum level of superoxide dismutase(SOD)in piglets on d 14,as well as increased(P<0.05)the serum FRAP level in piglets on d 28.ESBM decreased(P<0.05)serum levels of DAO and IL-1b in piglets compared with HWP on d 28.ESBM enhanced(P<0.05)the relative abundance of Bacteroidetes,Oscillospiraceae and Christensenellaceae,as well as reduced the relative abundance of Clostridiaceae in the feces compared with HWP and FSBM.The PICRUSt analysis revealed that the number of gene tags related to degradation of valine,leucine and isoleucine,as well as lysine degradation in ESBM were lower(P<0.05)than that in HWP and FSBM.ESBM increased(P<0.05)the fecal butyrate level in piglets compared with FSBM,and ESBM tended to decrease(P=0.076)the fecal cadaverine level.Overall,ESBM had advantages over HWP and FSBM in improving antioxidant status,immune function,fecal bacteria and metabolites for weaned piglets.     

Dogs are more permissive than cats or guinea pigs to experimental infection with a human isolate of Bartonella rochalimae

Bartonella rochalimae was first isolated from the blood of a human who traveled to Peru and was exposed to multiple insect bites. Foxes and dogs are likely natural reservoirs for this bacterium. We report the results of experimental inoculation of two dogs, five cats and six guinea pigs with the only human isolate of this new Bartonella species. Both dogs became bacteremic for 5–7 weeks, with a peak of 10³–10⁴ colony forming units (CFU)/mL blood. Three cats had low bacteremia levels (< 200 CFU/mL) of 6–8 weeks’ duration. One cat that remained seronegative had two bacterial colonies isolated at a single culture time point. A fifth cat never became bacteremic, but seroconverted. None of the guinea pigs became bacteremic, but five seroconverted. These results suggest that dogs could be a reservoir of this strain of B. rochalimae, in contrast to cats and guinea pigs.     

Serum levels of the immunoglobulins IgG and IgG(T) in horses

Levels of the immunoglobulins IgG and IgG(T) in serum in Norwegian horses of the breeds “Døle” and “Fjord” were determined by the quantitative radial immunodiffusion test.No significant differences were apparent between the 2 Norwegian breeds. The immunoglobulin levels were approximately in the same range as previously reported for Shetland ponies.Immunoglobulins could not be detected in the newborn foal. As early as 24 hrs. after birth the mean immunoglobulin level was within the adult range. After a drop during the first month of life, the immunoglobulins increased. IgG(T) rose more rapidly and to a higher level than IgG.In 2 year old horses, IgG(T) was significantly higher than in adults, while IgG was significantly lower. IgG(T) seems to be a very important immunoglobulin in foals and young horses.     

Glutamic acid supplementation recovers the reduced performance of weanling pigs fed reduced crude protein diets

This study was conducted to evaluate the supplementation of glutamic acid(Glu)to reduced protein diets on the performance of weanling pigs.One hundred and eighty crossbred weanling pigs([Yorkshire
Landrace]
Duroc,21 d old)having similar body weight(BW)of 6.45 kg were randomly allotted to 1 of 6 dietary treatments(5 pigs per pen[2 barrows and 3 gilts];6 pens per treatment)based on BW and sex during a 6-week trial.Dietary treatments consisted of positive control(PC)diet formulated to have 226.9,205.6,and 188.8 g crude protein(CP)during phases 1,2,and 3,respectively,and negative control(NC)diets with 20 g CP reduction from PC diets and addition of Glu with increasing levels,resulting in the calculated Lys-to-Glu ratios of 1:2.25,1:2.30.1:2.35,1:2.40,and 1:2.45,designated as NC,NC1,NC2,NC3,and NC4,respectively.The BW of pigs receiving PC diet was higher(P<0.05)than those receiving NC diet at d 7,21 and 42.A higher(P<0.05)average daily gain(ADG)from d 1 to 7,8 to 21,22 to 42 and during the overall experiment period was observed in pigs fed PC than NC diet.Pigs fed NC diets including the graded level of Glu linearly increased(P<0.05)BW at d 42,ADG and gain-to-feed ratio(G:F)during the overall experimental period.In addition,trends in linear increase in BW(P=0.056)at d 7 and ADG from d 1 to 7 and d 22 to 42(linear effect,P=0.081,P=0.058 respectively)were observed.A tendency in the linear increment of NH3(P=0.082)at d 21 and linear reduction in methyl mercaptans(P=0.054)emission at d 42 was observed in pigs fed NC diets supplemented with graded level of Glu.In conclusion,supplementing the reduced protein diet with Glu enhanced the growth performance in weanling pigs suggesting that supplementation of Glu can compensate the reduction of 2%CP in the basal diets.     

Seroprevalence of Leptospira Hardjo in the Irish suckler cattle population

Background

Prior to the present study, the seroprevalence of leptospirosis in Irish suckler herds was unknown. In this study, we describe the herd and animal-level prevalence of Leptospira Hardjo infection in the Irish suckler cattle population. For the purposes of the study, the 26 counties of the Republic of Ireland were divided into 6 regions from which a representative number of herds were selected. A herd was considered eligible for sampling if it was not vaccinating against leptospirosis and if it contained ≥ 9 breeding animals of beef breed ≥ 12 months of age. In total, 288 randomly selected herds were eligible for inclusion in the seroprevalence dataset analysis. Serological testing was carried out using a commercially available monoclonal antibody-capture ELISA, (sensitivity 100%; specificity 86.67%).

Results

Herds were categorised as either “Free from Infection” or “Infected” using the epidemiological software tool, FreeCalc 2.0. Using this classification, 237 herds were “Infected” (82.29%). The South West and South East regions had the highest herd prevalence. The regional effect on herd prevalence was largely mirrored by breeding herd size. A true animal-level prevalence of 41.75% was calculated using the epidemiological software tool, TruePrev. There was a statistically significant regional trend, with true prevalence being highest in the South East (P < 0.05). The median Breeding Herd Size (BHS), when categorised into quartiles, had a statistically significant influence on individual animal true seroprevalence (P < 0.001); true seroprevalence increased with increasing BHS.

Conclusions

Leptospirosis is a widespread endemic disease in the Republic of Ireland. It is possible that economic losses due to leptospirosis in unvaccinated Irish suckler herds may be underestimated.     

N-Acetyl-D-glucosamine improves the intestinal development and nutrient absorption of weaned piglets via regulating the activity of intestinal stem cells

Early weaning in piglets can cause a series of negative effects.This causes serious losses to the livestock industry.N-Acetyl-D-glucosamine(D-GlcNAc)plays an important role in regulating the homeostasis of the intestine.This study aimed to investigate the effects of D-GlcNAc on the growth performance and intestinal function of weaned piglets.Twenty-four weaned piglets([Yorkshire×Landrace]
Duroc,6.58±0.15 kg,n=8)at 21 d old were fed 3 diets supplemented with 0(control),1 and 3 g/kg D-GlcNAc.The intestinal organoid model was used to verify the regulatory mechanism of D-GlcNAc on intestinal epithelial cells.On the whole,supplementation of D-GlcNAc in the piglet diet has no significant effect on the growth performance and diarrhoea of weaned piglets(P>0.05).The apparent digestibility of nutrients and mRNA abundance of nutrient transporters in the 1 g/kg D-GlcNAc group were increased significantly(P<0.05).D-GlcNAc did not affect villus height(VH)and crypt depth(CD)but resulted in a numerically shorter VH and shallower CD,which lead to an increase in ileal VH:CD ratio(P<0.05).Cell shedding rates in the ileum villi increased(P<0.05).The relative length and weight of the small intestine of weaned piglets increased(P<0.05).In vitro studies found that the budding rates of organoids treated with 0.1 mmol/L D-GlcNAc increased on the d 3 and 5(P<0.05).The average budding numbers per budding organoid treated with 0.1 and 10 mmol/L D-GlcNAc increased on d 3(P<0.05).D-GlcNAc upregulated leucine rich repeat containing G protein-coupled receptor 5(Lgr5⁺)and Chromogranin A mRNA abundance in organoids(P<0.05).Mucin 2(Muc2)expression increased when treated with 1 and 10 mmol/L D-GlcNAc(P<0.05).In conclusion,dietary D-GlcNAc cannot improve the growth performance of weaned piglets.However,it can promote the growth and development of the intestinal tract and improve the digestion and absorption capacity of the intestine,which is achieved by affecting the activity of intestinal stem cells.     

Determination of optimal dietary selenium levels by full expression of selenoproteins in various tissues of broilers from 22 to 42 d of age

The current NRC dietary selenium(Se)requirement(0.15 mg/kg)of broilers from 22 to 42 d of age is primarily based on a previous study reported in 1986,which might not be applicable to modern classes of rapidly growing broilers.The present experiment was conducted to determine the optimal dietary Se level for meeting metabolic and functional Se requirements of broilers fed a corn-soybean meal diet from 22 to 42 d of age.A total of 336 Arbor Acres male broilers at 22 d old were randomly assigned to 1 of 6 treatments with 7 replicates and fed a basal corn-soybean meal diet(control,containing 0.014 mg Se/kg)and the basal diet supplemented with 0.10,0.20,0.30,0.40,or 0.50 mg Se/kg from Na₂SeO₃ for 21 d.The results showed that the Se concentrations in plasma,liver,kidney,pancreas,breast and thigh muscles,the activity of glutathione peroxidase(GPX)in plasma,liver and kidney,the mRNA expression levels of Gpx4,selenoprotein(Seleno)h and Selenou in liver,Selenop and Selenoh in kidney,and the protein expression levels of GPX4 in the liver and kidney of broilers were affected(P<0.05)by supplemental Se level,and increased quadratically(P<0.05)with the increase of supplemental Se level.The estimates of optimal dietary Se levels were 0.10 to 0.49 mg/kg based on the fitted broken-line or asymptotic models(P<0.0001)of the above Se concentration indices,and 0.08 to 0.37 mg/kg based on the fitted brokenline,quadratic or asymptotic models(P<0.007)of the above selenoprotein expression indices.These results indicate that the optimal dietary Se levels would be 0.49 mg/kg to support the maximum Se concentrations and 0.37 mg/kg to support the full expression of selenoproteins in plasma and various tissues of broilers fed a corn-soybean meal diet from 22 to 42 d of age.