Dietary stimulation of the endogenous somatotropic axis in weaner and growerfinisher pigs using medium chain triglycerides and cysteamine hydrochloride

Background： Three experiments were conducted to examine the overall hypothesis that addition of medium chain triglycerides（MCT） and cysteamine hydrochloride（CSH） into the diets of young and growing pigs would stimulate the endogenous somatotropic axis to improve growth and performance.Results： In Experiment 1, weaner pigs were given either a 5 d dietary supplement of 5 % MCT（n = 8） or a control diet（n = 8）. MCT increased the plasma concentration of growth hormone（GH; P ＆lt; 0.05） and the GH secretagogue,ghrelin（P ＆lt; 0.05）. Additionally, the MCT treatment reduced scouring（P ＆lt; 0.05）, maintained villous height in the small intestine（P ＆lt; 0.05） and stabilised daily weight gain（P ＆lt; 0.05）, compared to the controls. Experiment 2compared the effects of 4 levels（0, 1, 3 and 6 % v/v） of MCT supplementation in grower-finisher male pigs, of approximately 35 kg live weight（n = 15 per treatment）. Blood samples taken after 7 wk of treatment showed that the MCT supplementation increased circulating ghrelin（P ＆lt; 0.001）, GH（P ＆lt; 0.01） and insulin（P ＆lt; 0.05）concentrations in a dose-dependent manner. Daily weight gain, feed intake and feed conversion ratio were not affected by the MCT diets. In Experiment 3, 64 female pigs of approximately 60 kg live weight were allocated to one of three dietary treatments： control（n = 20）; 6 % MCT（n = 21）; and 70 mg/kg CSH（n = 21）. After 3 wk of supplementation, the MCT treated pigs had a higher plasma concentration of ghrelin compared to the control and CSH pigs（P ＆lt; 0.05）. Plasma concentrations of GH and weight were not affected by any of the dietary treatments.Conclusions： Evidence is provided in Experiment 1 to support the use of dietary MCT supplements, perhaps acting via stimulation of somatotropic endocrine pathways, to minimise weaning-associated disorders such as slowing of growth and diarrhoea. In Experiments 2 and 3, although there was no effect on weight gain or feed conversion ratio in either experiment, MCT and CSH increased endocrine components of the somatotropic axis.

Gestational heat stress alters skeletal muscle gene expression profiles and vascularity in fetal pigs in a sexually dimorphic manner

Background: There is evidence that sow heat stress(HS) during gestation affects fetal development with implications for impaired muscle growth. We have previously demonstrated that maternal HS during early to midgestation compromised muscle fibre hyperplasia in developing fetal pigs. Thus, we hypothesised these phenotypic changes are associated with a change in expression of genes regulating fetal skeletal muscle development and metabolism. To test this, at d 60 of gestation, RNA sequencing and immunohistochemistry were performed on fetal longissimus dorsi(LD) muscle biopsies collected from pregnant gilts that had experienced either thermoneutral control(CON, 20 ℃, n = 7 gilts, 18 LD samples) or controlled HS(cyclic 28 to 33 ℃, n = 8 gilts, 23 LD samples)conditions for 3 weeks.Results: A total of 282 genes were differentially expressed between the HS and CON groups in female LD muscles(false discovery rate(FDR) ≤ 0.05), whereas no differentially expressed genes were detected in male LD muscles between the two groups(FDR > 0.05). Gestational HS increased the expression of genes associated with transcription corepressor activity, adipogenesis cascades, negative regulation of angiogenesis and pro-inflammatory signalling in female LD muscles. Immunohistochemical analyses revealed a decreased muscle vascularity density in fetuses from HS group for both sexes compared to those from the CON group(P = 0.004).Conclusions: These results reveal gilt HS during early to mid-gestation altered gene expression profiles in fetal LD muscles in a sexually dimorphic manner. The molecular responses, including transcription and angiogenesis repressions and enhanced adipogenesis cascades, were exclusively observed in females. However, the associated reductions in muscle vascularity were observed independently of sexes. Collectively this may indicate female fetal pigs are more adaptive to gestational HS in terms of gene expression changes, and/or there may be sexually dimorphic differences with respect to the timing of muscle molecular responses to gestational HS.

日粮中添加中链甘油三酯和半胱胺酸盐对断 奶仔猪和生长育肥猪内源性生长轴的影响

该文通过3个试验来检验总体假设,即在仔猪和生长猪的日粮中添加中链甘油三酯(MCT)和半胱胺酸盐(CSH)将会刺激其内源性生长轴,从而改善其生长和性能。试验1结果显示:日粮中添加MCT增加了断奶仔猪血浆中生长激素(GH)(P<0.05)和生长激素促分泌素(Ghrelin)的浓度(P<0.05)。此外,与对照组相比,MCT处理组减少了仔猪腹泻(P<0.05),维持了其小肠绒毛高度(P<0.05)且仔猪日增重稳定(P<0.05)。试验2结果显示,MCT的添加增加了生长激素促分泌素(Ghrelin)(P<0.001)、GH(P<0.01)和胰岛素(P<0.05)的浓度,且呈现出剂量依赖性;而日粮中添加MCT对猪只的日增重、采食量和饲料转化率无影响。试验3结果显示,饲喂3周后,与对照组和CSH处理组相比,MCT处理组的猪只血浆Ghrelin浓度明显升高(P<0.05),而血浆GH浓度和体重则不受任何处理的影响。结论:试验1的结果表明日粮中添加MCT,可能是通过刺激生长激素内分泌途径将断奶相关病症(例如生长迟缓和腹泻)降到最低。在试验2和试验3中,尽管MCT和CSH的添加对猪只的增重或饲料转化率没有影响,但是增加了其生长轴的内分泌组分。

Nano-chromium picolinate and heat stress enhance insulin sensitivity in cross-bred sheep

This study evaluated the effects of heat stress(HS)and dietary nano chromium picolinate(nCrPic)on metabolic responses of sheep to an intravenous glucose tolerance test(IVGTT),an intravenous insulin tolerance test(ITT)and an intramuscular adrenocorticotropin hormone(ACTH)challenge in sheep.Thirty-six sheep housed in metabolic cages were randomly allocated within 3 dietary groups(0,400 and 800 mg/kg supplemental nCrPic)to either thermoneutral(22℃)or cyclic HS(22 to 40℃)conditions for 3 wk.Basal plasma glucose tended to be increased during HS(P=0.052)and decreased by dietary nCrPic(P=0.013)while plasma non-esterified fatty acid concentrations were decreased(P=0.010)by HS.Di-etary nCrPic reduced the plasma glucose area under the curve(P=0.012)while there were no significant effects of HS on plasma glucose area under the curve in response to the IVGTT.The plasma insulin response over the first 60 min after the IVGTT was decreased by HS(P=0.013)and dietary nCrPic(P=0.022)with the effects being additive.In response to the ITT plasma glucose reached a nadir sooner(P=0.005)in sheep exposed to HS,although there was no effect on the depth of the nadir.Dietary nCrPic decreased(P=0.007)the plasma glucose nadir after ITT.Over the duration of the ITT plasma insulin concentrations were lower in sheep exposed to HS(P=0.013)whereas there was no significant effect of supplemental nCrPic.There was no effect of either HS or nCrPic on cortisol response to ACTH.Dietary nCrPic supple-mentation decreased(P=0.013)mitogen-activated protein kinase-8(JNK)and increased(P=0.050)carnitine palmitoyltransferase 1B(CPT1B)mRNA expression in skeletal muscle.Results of this experiment demonstrated that animals under HS and supplemented with nCrPic had greater insulin sensitivity.

Post-weaning and whole-of-life performance of pigs is determined by live weight at weaning and the complexity of the diet fed after weaning

The production performance and financial outcomes associated with weaner diet complexity for pigs of different weight classes at weaning were examined in this experiment. A total of 720 weaner pigs(360 entire males and 360 females) were selected at weaning(27 ± 3 d) and allocated to pens of 10 based on individual weaning weight(light weaning weight: pigs below 6.5 kg; medium weaning weight: 6.5 to8 kg; heavy weaning weight: above 8.5 kg). Pens were then allocated in a 3 x 2 x 2 factorial arrangement of treatments with the respective factors being weaning weight(heavy, medium and light; H, M and L,respectively), weaner diet complexity(high complexity/cost, HC; low complexity/cost, LC), and gender(male and female). Common diets were fed to both treatment groups during the final 4 weeks of the weaner period(a period of 39 days). In the first 6 d after weaning, pigs offered the HC diets gained weight faster and used feed more efficiently than those offered the LC diets(P = 0.031). Pigs fed a HC diet after weaning tended to be heavier at the sale live weight of 123 d of age compared with pigs fed the LC diet(P = 0.056). There were no other main effects of the feeding program on growth performance through to slaughter. Weaning weight had a profound influence on lifetime growth performance and weight at 123 d of age, with H pigs at weaning increasing their weight advantage over the M and L pigs(101.3,97.1, 89.6 kg respectively, P < 0.001). Cost-benefit analyses suggested there was a minimal benefit in terms of cost per unit live weight gain over lifetime when pigs were offered a HC feeding program to L,with a lower feed cost/kg gain. The results from this investigation confirm the impact of weaning weight on lifetime growth performance, and suggest that a HC feeding program should be focused on L weaner pigs(i.e., weaning weight less than 6.5 kg at 27 d of age) in order to maximise financial returns.

Acid-insoluble ash is a better indigestible marker than chromic oxide to measure apparent total tract digestibility in pigs

The aim of this study was to determine the apparent total tract digestibility(ATTD)of nutrients in cottonseed meal(CSM)and soybean meal(SBM)in simple carbohydrate and more complex wheat-based diets using 2 indigestible markers and total faecal collection.Twenty-five Large White×Landrace boars(57.8 kg)were randomly allocated to either a pure wheat diet,40%CSM or SBM in either a sugar-starch-(1∶1)or wheat-based diet for 18 d.Acid-insoluble ash(AIA)and chromic oxide(Cr2O3)were included in all diets as indigestible markers.Diets were offered(1,800 g/d per pig)in 3 meals/d from d 1 to 11 and 8 meals/d from d 12 to 17.On d 9,the pigs were moved to individual metabolism cages to allow total faecal collection.On d 18,the pigs were fed hourly for 8 h.After the 8th meal,pigs were anaesthetized and digesta sampled from the terminal ileum and rectum before lethal injection.There were no differences between ATTD of nitrogen(N)determined using AIA as a marker and measured by total faecal collection.On the other hand,the ATrD of N of diets containing CSM in sugar-starch-or wheat-based diets and the pure wheat diet determined using Cr2O3 as a marker was less(-3.11%,-4.46%and-6.59%;P<O.001)than that measured by total faecal collection.The ATTD of N determined using AIA as a marker was highly correlated with that measured using total faecal collection(P<0.001;R2=0.95).Similarly,the ATTD of N determined using Cr2O3 as a marker was correlated with that measured using total faecal collection,although the correlation was not quite as strong as using AIA(P<0.001;R2=0.87).Also,the slope of the regression line and the intercept were closer to unity and zero for the relationship when the ATTD of N was determined using AIA compared to Cr2O3 as an indigestible marker.The ATTD of organic and dry matter behaved similarly.These data demonstrate that the basal diet and choice of indigestible marker can substantially influence the ATTD and that the use of AIA as an indigestible marker is more suitable than Cr2O3 in digestibility studies in pigs.

Basal diet and indigestible marker influence apparent digestibilities of nitrogen and amino acids of cottonseed meal and soybean meal in pigs

This study was to determine the apparent ileal nitrogen(N)and amino acid digestibilities of cottonseed meal(CSM)and soybean meal(SBM)in simple carbohydrate-based and more complex wheat-based diets.Twenty five Large White × Landrace boars(40.9 kg)were randomly allocated to one of 5 dietary treatments:a wheat diet,40% CSM in either a sugar:starch(1:1)or wheat-based diet,or 40% SBM in either a sugar:starch or wheat-based diet for 14 d.All diets contained vitamins,minerals,and contained acid-insoluble ash(AIA)and Cr2 O3 as indigestible markers.Rations were offered(1,800 g/pig per d)in3 meals/d on d 1-11 and 8 meals/d on d 12-13.On d 14,the pigs were fed hourly for 8 h.After the 8 th meal,pigs were anaesthetised with isoflurothane,and ileal and faecal digesta sampled from the terminal ileum and rectum before lethal injection of barbiturate.Apparent ileal digestibility(AID)of N was greater(12.1%)when CSM was fed in the wheat-based diet as compared to the simple carbohydrate-based diet,whereas apparent ileal N digestibility of SBM was slightly lower(-4.5%)in the wheat-based diet as compared to the sugar:starch-based diet.Apparent ileal amino acid digestibility generally respondeds similarly to N.Therefore,while there was a wide difference in apparent N and amino acid digestibilities of SBM and CSM when they were fed in the sugar:starch-based diets,these differences were less apparent when they were fed the wheat-based diet.There was an apparent net release of N into the hindgut of pigs fed CSM in both base diets.Conversely,there was quite substantial apparent digestion of N in the hindgut of pigs fed SBM in both base diets.The use of Cr2 O3 as an indigestible marker resulted in lower apparent ileal and faecal digestibilities than using AIA,particularly for diets containing CSM.These data demonstrate that the basal diet and choice of indigestible marker can substantially influence the estimate of apparent N digestibility,this response can differ for different protein meals.

Dietary nano chromium picolinate can ameliorate some of the impacts of heat stress in cross-bred sheep

Two studies were conducted to evaluate the effect of nano chromium picolinate(nCrPic)during heat stress(HS)in sheep.In the initial study,36 Merino×Poll cross-bred sheep were individually penned and allocated to 3 dietary treatments(0,400 and 800μg/kg nCrPic)for 8 wk.Body composition was determined at the beginning and end of the experiment using dual energy X-ray absorptiometry.The sheep remained in their dietary groups but were then placed in metabolic cages and randomly allocated within the dietary group to differing ambient temperature regimes,i.e.,thermo-neutral(TN)(n=18)and HS(n=18),for 3 wk.Dietary nCrPic had no effect on growth performance and body composition during the initial study conducted under TN conditions.Heat stress decreased average daily feed intake(ADFI)(P=0.002)whereas sheep under HS had reduced average daily gain(ADG)and indeed lost weight(P<0.001).Dietary nCrPic increased both ADFI(P=0.041)and ADG(P=0.049)under both TH and HS conditions such that the performance of sheep receiving supplemental nCrPic and exposed to HS was similar to that of control sheep maintained under TN conditions.Heat stress increased rectal temperature(P<0.001)and respiration rate(P<0.001),particularly during the hottest parts of the day as indicated by interactions(P<0.001)between time of day and thermal treatment.Rectal temperature was lower in sheep fed nCrPic(P=0.050),particularly under peak HS conditions during the afternoon as indicated by the interactions between dietary nCrPic and time of day(P<0.001)and dietary nCrPic,thermal treat-ment and time of day(P=0.010).Similarly,respiration rate was lower in sheep fed nCrPic under peak HS conditions during the afternoon as indicated by the interactions between dietary nCrPic and thermal treatment(P<0.001)and dietary nCrPic and time of day(P=0.030).In conclusion,dietary nCrPic can partially ameliorate the negative effects of HS as indicated by the maintenance of ADFI and decreased physiological responses,such as elevations in rectal temperature and respiration rate.

Screening of phenolic compounds in australian grown grapes and their potential antioxidant activities

Grapes(Vitis Vinifera)are one of the world's most utilised and prized fruit.Grapes are a great source of antioxidants due to the abundance of phenolic compounds.Grape pulp is the main part of the grape being consumed.The pulp of five Australian grown grapes–Dawn Seedless(DS),Calmeria(CG),Golden Globe(GG),Menindee Seedless(MS),and Thompson Seedless(TS)will be qualitatively and quantitatively analysed for its phenolic composition and antioxidant capacity.The general trend followed:GG>TS>MS>DS>CG,and the phenolic content of the pulp also presented a significant positive correlation with the antioxidant capacity.GG revealing the highest levels of TPC(4.31±0.11 mg GAE/g)and TFC(0.48±0.09 mg QE/g)while TS were highest in TTC(0.94±0.12 mg CE/g).Similarly,GG exhibited higher antioxidant capacity in DPPH(5.84±0.17 mg AAE/g),FRAP(4.91±0.14 mg AAE/g),and TAC(6.78±0.12 mg AAE/g),while TS revealed highest radical scavenging ability for ABTS(4.56±0.19 mg AAE/g).The LC-ESI-QTOF-MS/MS tentatively identified 78 phenolic compounds consisting of flavonoids(36),phenolic acids(31),lignans(3),stilbenes(1),and other polyphenols(7)in five grapes samples.Ten most abundant fruit-based targeted polyphenols were quantified.GG had a higher phenolic concentration in HPLC-PDA quantification,particularly for phenolic acids(gallic acid and chlorogenic acid)and flavonoids(kaempferol).Our study provides relatively adequate information on grape pulp's phenolic content and antioxidant capacity,providing confidence and research prospects to promote grape pulp use in different food,pharmaceutical and supplement industries,and even influencing grape cultivation.

Effect of processing on bioaccessibility and bioavailability of bioactive compounds in coffee beans

Coffee is one of the most prevalent and functional beverages around world owing to its rich content of bioactive compounds.Phenolic compounds and alkaloids are two primary groups of bioactive compounds in coffee beans,which have been proven healthy benefits in regular and suitable daily consumption.They have been recognized as protective factors,especially phenolic compounds,to perform high antioxidant capacities and potential to relieve the occurrence of chronic diseases and partial cancer.The content and composition of bioactive and anti-nutritional compounds in coffee beans can be mainly influenced by variety,processing and storage conditions.The cultivar of Arabica coffee beans(C.arabica)exhibits lower content of phenolic compounds but similar anti-nutritional substances with the comparison to Robusta(C.canephora).Comparing to green coffee beans,reasonable roasting contributes to the improvement of phenolic content and its total antioxidant activity because of the liberation of bound phenolic compounds and the generation of novel compounds with antioxidant activity.Over intensive roasting will not only decrease the number of bioactive compounds within the coffee beans but also stimulate the generation of endogenous anti-nutritional compounds,which consequently reduce the coffee nutritional value.The fluctuations of moisture content during storage would be the primary reason of the changes in the content of bioactive compounds.Phenolic compounds in coffee beans perform outstanding bioaccessibility but relatively lower absorption efficiency because of the combination with other molecules.Suitable roasting would improve the bioavailability of bioactive compounds.The interaction between phenolic compounds and proteins would also influence the bioavailability and bioactivity of bioactive compounds and final nutritional value after consumption.