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The purpose of this study was to investigate the effects of dietary L-theanine supplementation on apparent nutrient digestibility, milk yield, milk composition, and blood biochemical indices of dairy cows under heat stress. Thirty Chinese Holstein cows (19.84 ± 2.42 kg milk/d, 192.36 ± 40.77 d in milk and 2 ± 0.93 parities) were divided into 3 groups of 10 animals each. The control group was fed a basal total mixed ration (TMR) diet, while treatment 1 (LTA16) and treatment 2 (LTA32) groups were fed a basal TMR diet supplemented with L-theanine at 16 and 32 g/cow per day, respectively. The results showed that feeding the dairy cows with LTA16 treatment decreased (

Objective: The effects of maternal undernutrition during midgestation on muscle fiber histology, myosin heavy chain (MyHC) expression, methylation modification of myogenic factors, and the mammalian target of rapamycin (mTOR) signaling pathway in the skeletal muscles of prenatal and postnatal goats were examined.Methods: Twenty-four pregnant goats were assigned to a control (100% of the nutrients requirement, n = 12) or a restricted group (60% of the nutrients requirement, n = 12) between 45 and 100 days of gestation. Descendants were harvested at day 100 of gestation and at day 90 after birth to collect the femoris muscle tissue.Results: Maternal undernutrition increased (p

The biological mechanism by which maternal undernutrition increases the metabolic disorder risk of skeletal muscles in offspring is not fully understood. We hypothesize that maternal intake restriction influences metabolic signals in the skeletal muscles of offspring via a glucagon-mediated pathway. Twenty-four pregnant goats were assigned to the control group (100% of the nutrients requirement, n = 12) and restricted group (60% of the control feed allowance from pregnant days 45 to 100, n = 12). Blood and Longissimus thoracis muscle were sampled from dams (100 d of gestation), fetuses (100 d of gestation), and kids (90 d after birth) in each group. The data were analyzed using the linear MIXED model, with the multiple comparison method of SIDAK applied. Intake restriction reduced (P

Ramie (Boehmeria nivea) is noted for the production of a large biomass that has a high protein content and is rich in antioxidants. It may thus serve as a high-quality forage material to replace alfalfa and improve the meat quality of farmed animals. In this study, we evaluated the carcass characteristics and meat quality of goats when 0, 35%, 75%, and 100% of dietary alfalfa was replaced with ramie. Crude protein content (linear, P

Background Methionine or lysine has been reported to influence DNA methylation and fat metabolism, but their combined effects in N6-methyl-adenosine (m6A) RNA methylation remain unclarified. The combined effects of rumen-protected methionine and lysine (RML) in a low-protein (LP) diet on lipid metabolism, m6A RNA methylation, and fatty acid (FA) profiles in the liver and muscle of lambs were investigated. Sixty-three male lambs were divided into three treatment groups, three pens per group and seven lambs per pen. The lambs were fed a 14.5% crude protein (CP) diet (adequate protein [NP]), 12.5% CP diet (LP), and a LP diet plus RML (LP + RML) for 60 d. Results The results showed that the addition of RML in a LP diet tended to lower the concentrations of plasma leptin (P = 0.07), triglyceride (P = 0.05), and non-esterified FA (P = 0.08). Feeding a LP diet increased the enzyme activity or mRNA expression of lipogenic enzymes and decreased lipolytic enzymes compared with the NP diet. This effect was reversed by supplementation of RML with a LP diet. The inclusion of RML in a LP diet affected the polyunsaturated fatty acids (PUFA), n-3 PUFA, and n-6 PUFA in the liver but not in the muscle, which might be linked with altered expression of FA desaturase-1 (FADS1) and acetyl-CoA carboxylase (ACC). A LP diet supplemented with RML increased (P 6A levels in the liver and muscle and were accompanied by decreased expression of fat mass and obesity-associated protein (FTO) and alkB homologue 5 (ALKBH5). The mRNA expressions of methyltransferase-like 3 (METTL3) and methyltransferase-like 14 (METTL14) in the LP + RML diet group were lower than those in the other two groups. Supplementation of RML with a LP diet affected only liver YTH domain family (YTHDF2) proteins (P YTHDF3 (P = 0.09), which can be explained by limited m6A-binding proteins that were mediated in mRNA fate. Conclusions Our findings showed that the inclusion of RML in a LP diet could alter fat deposition through modulations of lipogenesis and lipolysis in the liver and muscle. These changes in fat metabolism may be associated with the modification of m6A RNA methylation. Graphical abstract A systematic graph illustrates the mechanism of dietary methionine and lysine influence on lipid metabolism and M6A. The green arrow with triangular heads indicates as activation and brown-wine arrows with flat heads indicates as suppression.

The colon is a crucial digestive organ of the hind gut in ruminants. The bacterial diversity and mucosal immune maturation in this region are related to age. However, whether the microRNA expression in the colon of goats is affected by age is still unclear. In the current study, we analyzed the transcriptomes of colon microRNAs during preweaning (Day 10 and Day 25) and postweaning (Day 31). A total of 1572 microRNAs were identified in the colon tissues. Of these, 39 differentially expressed microRNAs (DEmiRNAs) and 88 highly expressed microRNAs (HEmiRNAs) were screened. The target genes regulated by the DEmiRNAs and HEmiRNAs were commonly enriched in the MAPK signaling pathway, Wnt signaling pathway, Hippo signaling pathway, cell adhesion molecules, focal adhesion, and adherens junction. Remarkably, the targeted genes of the DEmiRNAs were highly enriched for the prevention of microbial invasion via the Erbb−MAPK network while the targeted genes of HEmiRNAs contributed to the permeable barrier maintenance and cell damage surveillance. Additionally, there were eight different expression profiles of 87 dynamic miRNAs, in which approximately half of them were affected by age. Taken together, our study reveals the different roles of DEmiRNAs, HEmiRNAs, and dynamic microRNAs in the development of the colon and gives new insights into the regulatory mechanism of colon development in goats.

Background Liver has important immune function during fetal development and after birth. However, the effect of maternal malnutrition on immune function of the fetal liver is rarely reported. In this study, twelve pregnant goats (Xiangdong black goat, at d 45 of gestation) were assigned to the control group (fed 100% of nutritional requirements) and the restriction group (fed 60% of the intake of the control group) during gestation from d 55 to 100. Fetal goats were harvested at d 100 of gestation and immune indexes and amino acid profiles of the umbilical cord blood and liver Toll-like receptors (TLRs) signaling pathways were measured. Results Maternal body weight in the restriction group was lower than the control group (P P < 0.05) heart weight, heart index, alkaline phosphatase and serum amyloid protein A in the umbilical cord blood (UCB). Moreover, only histidine was decreased in the restricted group (P = 0.084), and there were no differences in other amino acids contents in the UCB between the two groups (P > 0.05). The TLR2 and TLR4 mRNA expression in the fetal liver in the restriction group was greater (P < 0.05) than that in the control group. Furthermore, the mRNA expression levels of myeloid differentiation primary response 88 (MyD88), TNF receptor associated factor 6, nuclear factor kappa B subunit 1, NFKB inhibitor alpha, IFN-β, TGF-β, TNF-α and IL-1β in the restricted group were upregulated (P < 0.05), and the expression of TLR3 (P = 0.099) tended to be higher in the restricted group. However, protein levels of TLR2, TLR4, IκBα, phosphorylated IκBα, phosphorylated IκBα/total IκBα, TRIF and MyD88 were not affected (P > 0.05) by maternal intake restriction. Conclusions These results revealed that the restriction of maternal feed intake influenced the development of heart and hepatic protein synthesis at the acute phase of fetal goats and upregulated the mRNA expression of genes involved in MyD88-dependent signaling pathways and of target cytokines.

The objective of this study was to investigate the variations in nutrient digestibility, rumen fermentation, serum biochemical parameters, and performance resulting from an increase in the proportion of ramie (Boehmeria nivea) substitution for alfalfa in the diets of goats. In a completely randomized block design, thirty-two Liuyang black goats were divided into two blocks according to body weight (BW) (light, BW: 16.7 ± 1.72 kg; and heavy, BW: 26.6 ± 2.95 kg). Then, the sixteen goats in each block were further randomly divided into four subgroups that randomly accepted four treatments, i.e., alfalfa was replaced by ramie at 0%, 35%, 70% and 100%. The results showed that the apparent digestibility of gross energy (GE) (linear, p 0.05) by the inclusion of ramie. The concentration of ammonia nitrogen (NH3-N) in the rumen fluid decreased (linear, p

Effects of a high proportion of concentrate in the diet on the ileal microbiota and metabolites in small ruminants are rarely reported. This study was designed to investigate the ileal microbiota and its relationship with host metabolic function in goats and aimed to elucidate the mechanisms involving in the ileal adaptation to a diet containing a high proportion of rice. Sixteen goats were equally divided into two groups and fed a diet with a normal concentrate proportion (NC, 55% concentrate) or a high-concentrate diet (HC, 90% concentrate). Results showed that the HC diet decreased bacterial diversity and elevated the abundance of five genera (Clostridium_sensu_stricto_1, Eubacterium_nodatum_group, Ruminococcus_gauvreauii_group, Eubacterium_coprostanoligenes_group and Ruminococcus 1), but reduced the number of Anaerotruncus. Microbial functional potentials indicated that the HC diet activated the pathways related to metabolism of carbohydrate, glycan, lipid and vitamins, but inhibited the pathways associated with cell motility and signal transduction. The activities of amylase and alkaline phosphatase were greater (p &lt, 0.05) in the intestinal digesta of the HC-fed goats. However, there were no differences in the villus height, crypt depth and the ratio of villus height to crypt depth in the ileum between the two groups. These results indicate that the HC diet alters the bacterial community and pathways related to the metabolism of dietary nutrients and cell motility and signal transduction of bacteria in the ileum of goats.

Weaning usually leads to stress in livestock, which has a negative impact on their growth and development. Research on oxidative stress and inflammation induced by weaning has not been reported in goats. Here, we focused on oxidative stress profile and inflammation status of the lower gut (jejunum, ileum, and colon) of goats. First, we illustrated the status of antioxidant activity and inflammation in the intestine of young goats on pre-(2 weeks postnatal, 2 wkpn) or post-(11 wkpn, weaning at day 45 postnatal)-weaned period of young goats. Malondialdehyde (MDA) was higher (p &lt, 0.0001) in jejunum and ileum of the young goats in 11 wkpn than that in 2 wkpn, whereas superoxide dismutase (SOD) activity was lower (p = 0.012) in the lower gut of the young goats with 11 wkpn than that in 2 wkpn. Furthermore, we intended to explore the protective influence of a probiotic additive (Lactobacillus plantarum (LAC) P-8, 10 g/d) and a prebiotic additive (Sangrovit&reg, Macleaya cordata (MAC) extract 3.75% w/w premix, 0.3 g/d) on intestinal oxidative stress and inflammation status of early-weaned young goats (average weights of 5.63 &plusmn, 0.30 kg, weaned on d 45 postnatal). We observed that LAC reduced MDA in jejunum and ileum (p &lt, 0.0001), increased SOD activity in ileum (p &lt, 0.01), and increased glutathione peroxidase (GSH-Px) activity in jejunum (p &lt, 0.05). Similarly, MAC reduced MDA contents (p &lt, 0.0001), increased SOD activities (p &lt, 0.01) in both of ileum and jejunum, and increased GSH-Px activity (p &lt, 0.05) in jejunum. However, there were no differences in feed intake, average daily gain, inflammation parameters (interleukin 2 and interleukin 6), and colon oxidative stress profile (MDA, SOD, or GSH-Px) among treatments. These results provide evidence that weaning induces oxidative damage in the lower gut of young goats, and the oxidative damage in the small intestine can be reduced by adding the addition of LAC or MAC in diets depending on the region of the lower gut.

Maternal nutrition during gestation is a leading factor of modifying the foetal epigenome and phenotype for mammals. Imprinting genes have important roles in regulating foetal growth, programming and development. There, however, are limited data available on the effects of feed intake restriction on the expression of imprinting genes in pregnant goats. The present study, therefore, was conducted to assess the effects of maternal feed intake restriction on the relative abundance of mRNA for growth imprinting, DNA methyltransferase (DNMT) and epigenetic transcription-related genes in the liver and heart of foetal goats during gestation. A total of 24 Liuyang black goats (2.0±0.3 yr) with similar body weight (BW, 31.22±8.09 kg) and parity (2) were allocated equally to either a control group (CG) or a restriction group (RG) during both early (from 26 to 65 days) and late (from 96 to 135 days) gestation. All goats were fed a mixed diet and had free access to fresh water. The feed of the RG was 40% less than that of the CG. The early and late gestation goats were weighed, bled and slaughtered on days 65 and 135 of gestation, respectively. In early gestation, the foetal weight, body length, the weight of foetal heart and liver were greater (P 0.05) in the RG. The CpG methylation of genomic DNA in the foetal heart was less (P = 0.0001) in the RG. The relative abundance of mRNA of methyl-CpG-binding domain protein 2 (MBD2) and methyl-CpG-binding domain protein 3 (MBD3) genes in the foetal liver were greater (P 0.05) in the RG. During the late gestation, the foetal weight, heart weight and liver weight were less (P 0.05) in the RG. The relative abundance of mRNA for the MBD2 gene (P = 0.043) in the foetal heart, and the ten-eleven translocation protein 1 (TET1) gene (P 0.05) in both the foetal heart and liver were greater in the RG. These results indicate feed intake restriction during gestation influenced foetal development and regulated the relative abundance of mRNA for epigenetic transcription-related genes.

Studies associated with regional roughage utilisation in Tibetan sheep have been limited. This study focussed on the mechanism of lipid metabolism and deposition in Tibetan sheep fed local roughage sources. Twenty-four Tibetan sheep weighing 16.1 ± 1.76 kg were randomly assigned to two mixed diets containing the same concentrate mixed with oat grass (OG) or highland barley straw (HBS). The ME and CP of OG diet were 7.16 MJ/kg DM and 5.94%, respectively, while in HBS diet were 7.13 MJ/kg DM and 7.39%. Lipid profiles in the plasma and liver, fatty acid (FA) composition and lipogenetic genes expression in the muscle and adipose tissue were determined. No difference was observed in DMI, total cholesterol, triglyceride, low-density lipoprotein and high-density lipoprotein levels in the plasma and liver of sheep between two groups (p>.05). Plasma leptin and liver non-esterified fatty acid (NEFA) content in HBS group tended to be greater than that in OG group (p

Four levels of Momordica charantia polysaccharide (MCP) supplements (0, 0.1, 0.3, 0.6 mg/ml) were designed to investigate the effects of MCP on ruminal fermentation and cellulolytic bacteria in vitro. The pH, ammonia-N (NH3-N) and volatile fatty acids (VFA) were measured at 6, 24, 48 h, whilst the cellulolytic bacteria population was determined at 6 and 24 h. The 0.6 mg/ml MCP inclusion decreased the theoretical maximum of gas production and the half-life. The NH3-N concentration was decreased by MCP at all doses at 24 h. The MCP inclusion increased the concentration of total VFA at 24 and 48 h and the acetate to propionate ratio, the molar proportion of isovalerate at 6 h, while decreased that of isobutyrate at 24 h and that of isovalerate, valerate at 24 and 48 h, respectively. The relative abundances of Ruminococcus albus and Ruminococcus flavefaciens were decreased at 6 h, while that of Butyrivibrio fibrisolvens was increased at all times of incubation and that of Fibrobacter succinogenes reached the greatest value at 0.6 mg/ml MCP supplementation at 24 h. This study demonstrated that the MCP had the ability to enhance the total VFA production, modulate the rumen fermentation pathway and influence the number of cellulolytic bacteria population.

This study investigated the in vitro fermentation of three cereal straws (corn stover, wheat straw, and rice straw) with culture media containing two nonionic surfactants (alkyl polyglycoside and Tween 80) and variable surface tension (42, 48, and 54 mN/m) in a 2 × 3 factorial arrangement. The in vitro dry matter degradation of rice straw and corn straw linearly (P

The phytobiotic Macleaya cordata extract (MCE) has been widely used as a natural growth promoter in livestock production to alleviate intestinal inflammatory response. The objective of this study was to investigate the effects of dietary MCE inclusion on the transcriptomes and changes of immune function in the intestinal tract of early weaned goats. Twelve kid goats (with an average age 30 ± 2 d after birth) were selected and randomly assigned to the control group (CON, providing starter feed) and MAC group (starter feed with MCE at 0.3 g/d), and were harvested at d 46 of the experiment to collect ileal and colonic tissue samples for subsequent analyses. Colonic transcriptome analyses showed upregulated differential expressed genes (DEGs) mainly enriched in immune related processes including TNF signaling pathway, phagosome and NF-κB signaling pathway, however, downregulated DEGs involved in pancreatic secretion and bile secretion. To validate the DEGs mentioned above, we performed quantitative real-time PCR to determine the expression of genes in Toll-like receptor 4 signaling pathway (including TNF and NF-κB signaling pathway). Dietary MCE inclusion only affected (P

This trial was conducted to investigate the effects of feeding system and age on morphological development (including villus height, crypt depth, and ratio of villus height to crypt depth) and expression of hexose transporters (i.e., SGLT1, GLUT2 and GLUT5) in different segments of the small intestine of goat kids. A total of 40 Liuyang black goat kids were randomly slaughtered at 0, 7, 28, 42, 56 and 70 days of age. There were two feeding systems [i.e., supplemental feeding (S) and grazing (G)] from 28 to 70 days of age. Duodenal, jejunal and ileal tissues were collected to measure the villus height and crypt depth. Mucosa samples were taken to quantify mRNA or protein expression of sodium-dependent glucose-linked transporter-1 (SGLT1), facilitated glucose/fructose transporter 2 (GLUT2), and facilitated glucose transporter 5 (GLUT5). Villus height was not affected ( P > 0.05) by feeding system, and crypt depth was only affected ( P P = 0.006) with increasing age in the duodenum, whereas it decreased as age increased in the jejunum ( P = 0.040) and ileum ( P P P P

In non-ruminants, sweet taste receptor and monosaccharide transporters are important components of nutrient chemosensing in the intestinal tracts. Ruminants, however, have evolved a polygastric digestive system linked to a transition in nutrient supply from readily-digestible carbohydrate (lactose) in milk during the pre-ruminant suckling phase to poorly-digestible structural carbohydrates when the rumen becomes functional. Whether these developmental and feed changes alter the mRNA expression of genes related to monosaccharide sensing (Taste receptor family 1 member 2, T1R2; Taste receptor family 1 member 3, T1R3) and transporting (monosaccharide transporters Na+/glucose co-transporter, SGLT1; glucose activated ion channel, SGLT3; solute carrier family 2 member 5, GLUT5; solute carrier family 2 member 2, GLUT2) are unknown. This study investigates the expression of sweet taste receptors (T1R2 and T1R3) and monosaccharides transporters (SGLT1, SGLT3, GLUT5 and GLUT2) along the gastrointestinal tracts (GIT) during different stages of development (suckling, weaning and grazing) in goats. The results showed that the expression of T1R2 decreased with age, and was mainly expressed in the duodenum and jejunum. Although T1R3 expression in different GIT segments fluctuated during growth, there was an increase with age, with the abomasum showing the greatest expression. Both SGLT1 and SGLT3 were mainly expressed in the jejunum at all ages, with the greatest expression in the middle jejunum during suckling, and decreased greatly (P

The objective of this study was to determine whether 13 C labeling occurs in goats fed diets with different natural levels of 13 C enrichment and, if so, to use 13 C as a label to determine true amino acid (AA) digestibility. Thirty-six Xiangdong black goats with initial body weights of 7.5 ± 0.5 kg were selected as experimental animals and fed dietary treatments consisting of wheat, barley, and soybeans (C3 diet) or corn, sorghum grain, and sugar cane (C4 diet). The 13 C abundance of the amino acid fraction (AAF) of the C3 and C4 diets had average delta 13 C values of −28.57‰ and −12.93‰, respectively. Three goats/treatment were slaughtered on days 1, 28, 56 and 84 during the labeling phase, and the AAFs of organs were analyzed for 13 C abundance. 13 C in the blood AAF increased (−21.70‰, −22.65‰, −23.59‰, and −24.43‰, respectively) with increasing feeding durations in goats fed the C3 diet and decreased (−21.13‰, −16.01‰, −13.78‰, and −12.03‰, respectively) in goats fed the C4 diet. Longissimus dorsi, liver and wool AAFs showed similar trends to those observed in the blood. Each tissue showed a significant dietary treatment effect ( P P 13 C abundance. 13 C abundance of the blood AAF was used as an index of endogenous protein labeling. Apparent and true protein digestibilities in the forestomach, whole intestine and whole digestive tract were not different ( P > 0.05) between the diet treatment groups. The levels of true protein digestibility in the forestomach, whole intestine and whole digestive tract in goats fed the C4 diet tended to be higher than for those in goats fed the C3 diet. On average, the true digestibilities of protein, essential AAs and nonessential AAs were 5.30%, 4.28% 3.17% (forestomach), 5.20%, 5.39% 3.75% (whole intestine) and 3.01%, 4.97%, 4.17% (whole digestive tract) higher, respectively, than the apparent digestibilities of these components in goats fed the C3 diet. In summary, goat tissue protein was labeled with 13 C using different diets, and the results show that 13 C can be used to determine true AA digestibility.

This study was conducted to investigate the effects of Momordica charantia saponin (MCS) on ruminal fermentation of maize stover and abundance of selected microbial populations in vitro. Five levels of MCS supplements (0, 0.01, 0.06, 0.30, 0.60 mg/mL) were tested. The pH, NH3-N, and volatile fatty acid were measured at 6, 24, 48 h of in vitro mixed incubation fluids, whilst the selected microbial populations were determined at 6 and 24 h. The high dose of MCS increased the initial fractional rate of degradation at t-value = 0 (FRD0) and the fractional rate of gas production (k), but decreased the theoretical maximum of gas production (V F) and the half-life (t0.5) compared with the control. The NH3-N concentration reached the lowest concentration with 0.01 mg MCS/mL at 6 h. The MSC inclusion increased (p

The objective of this study was to investigate the effects of maternal nutritional restriction on fetal growth and bone metabolism in early pregnancy. Twelve twin-bearing goats (Xiangdong black goats) in second pregnancy, with similar weight (31.2 ± 8.1 kg) and age (2.0 ± 0.3 year) were assigned to two dietary treatments in early gestation (26–65 days): control group (CON, 100% feed) and intake restriction group (IR, 60% of CON intake). The umbilical blood, right femur and liver of the fetuses were sampled on day 65 to determine the bone metabolism indicators and expression of genes involved in bone development. Maternal intake restriction did not affect the growth performance of pregnancies (P > 0.05), increased (P

Methane produced from formate is one of the important methanogensis pathways in the rumen. However, quantitative information of CH4 production from formate has been rarely reported. The aim of this study was to characterize the conversion rate (CR) of formic acid into CH4 and CO2 by rumen microorganisms. Ground lucerne hay was incubated with buffered ruminal fluid for 6, 12, 24 and 48 h. Before the incubation, 13C-labeled H13COOH was also supplied into the incubation bottle at a dose of 0, 1.5, 2.2 or 2.9 mg/g of DM substrate. There were no interactions (Pgt;0.05) between dose and incubation time for all variables evaluated. When expressed as an absolute amount (ml in gas sample) or a relative CR (%), both 13CH4 and 13CO2 production quadratically increased (Plt;0.01) with the addition of H13COOH. The total 13C (13CH4 and 13CO2) CR was also quadratically increased (Plt;0.01) when H13COOH was added. Moreover, formate addition linearly decreased (Plt;0.031) the concentrations of NH3-N, total and individual volatile fatty acids (acetate, propionate and butyrate), and quadratically decreased (Plt;0.014) the populations of protozoa, total methanogens, Methanosphaera stadtmanae, Methanobrevibacter ruminantium M1, Methanobrevibacter smithii and Methanosarcina barkeri. In summary, formate affects ruminal fermentation and methanogenesis, as well as the rumen microbiome, in particular microorganisms which are directly or indirectly involved in ruminal methanogenesis. This study provides quantitative verification for the rapid dissimilation of formate into CH4 and CO2 by rumen microorganisms.

This study was conducted to evaluate the effects of the dietary ratio of ruminal degraded protein (RDP) to ruminal undegraded protein (RUP) and the dry matter intake (DMI) on the intestinal flows of endogenous nitrogen (N) and amino acids (AA) in goats. The experiment was designed as a 4×4 Latin square using four ruminally, duodenally and ileally cannulated goats. The treatments were arranged in a 2×2 factorial design; two ratios of RDP to RUP (65:35 and 45:55, RDP1 and RDP2, respectively) and two levels at 95% and 75% of voluntary feed intake (DMI1 and DMI2, respectively) were fed to the goats. There were no significant differences in the N intake, duodenal flow of total N, undegraded feed N, microbial N, endogenous N or ileal flow of endogenous N, but the duodenal and ileal flow of endogenous N numerically decreased by approximately 22% and 9%, respectively, when the feed intake changed from DMI1 (0.63 kg/d) to DMI2 (0.50 kg/d). The dietary ratio of RDP to RUP had significant effects (p0.05) on the ileal flows of endogenous leucine, phenylalanine and cysteine. The present results implied that the duodenal flows of endogenous N and AA decreased when the dietary RDP to RUP ratio and DMI decreased, and the flow of endogenous AA at the ileum also decreased when the DMI decreased but increased with decreasing RDP to RUP ratios.

Nutritional status during mid-gestation is often ignored under extensive husbandry. This study aimed to examine the effect of maternal undernutrition during mid-gestation on kid meat production under an extensive system. Twenty-seven goats (45 &plusmn, 3 d of gestation) were randomly assigned to an unrestricted group (100% of nutrient requirements), or a restricted group (60% of nutrient requirements from 45 to 100 d of gestation, and then re-alimented to 100%). Among the offspring, 16 eligible kids (eight per treatment) were selected, based on birth type and survival, and were harvested to evaluate the meat yield, quality, and composition at 90 d after birth. Maternal undernutrition reduced the body weight and size, average daily gain and hot carcass weight of the kids (p &lt, 0.05). The lightness of the meat at 45 min postmortem was increased (p = 0.029) in the restricted kids. Apart from an increase in tyrosine concentration (p = 0.046), the proximate composition and the amino acid and fatty acid profiles were unaffected in the restricted kids (p &gt, 0.05). Overall, maternal undernutrition during mid-gestation decreased the yield of kid meat, but did not significantly modify the quality and composition. These results highlight the importance of nutrient status during mid-gestation in the meat production of small ruminants under an extensive regime.

Effects of energy, protein, or both energy and protein restriction on gastrointestinal morphological development were investigated in 60 Liuyang Black kids, which were sourced from local farms and weaned at 28 d of age. Weaned kids were randomly assigned to receive 1 of 4 dietary treatments (15 kids per treatment), which consisted of adequate nutrient supply (CON), energy restriction (ER), protein restriction (PR), or energy and protein restriction (EPR). The entire experiment included adaptation period (0 to 6 d), nutritional restriction period (7 to 48 d), and recovery period (49 to 111 d). Three kids from each group were killed at d 48 and 111, and the rumen, duodenum, jejunum, and ileum were harvested. On d 48 (end of nutritional restriction), lengths of the duodenum (P = 0.005), jejunum (P = 0.003), and ileum (P = 0.003), and weights of the rumen (P = 0.004), duodenum (P = 0.006), jejunum (P = 0.006), and ileum (P = 0.004) of kids in ER, PR, and EPR were less than those of kids in CON. Compared with CON, PR decreased papillae width (P = 0.03) and surface area (P = 0.05) of the rumen epithelium, villus surface area (P = 0.05), and N concentration (P = 0.02) of the jejunum mucosa on d 48. Compared with CON, EPR decreased papillae height (P = 0.001), width (P = 0.001), and surface area (P = 0.003), N concentration (P = 0.01), and the ratio of N to DNA (P = 0.03) of the rumen epithelium. Compared with CON, EPR also decreased villus height (P = 0.01), width (P = 0.006), and surface area (P = 0.006), N concentration (P < 0.001), and the ratio of N to DNA (P < 0.001) of the jejunum mucosa on d 48. On d 111 (end of nutritional recovery), lengths of the duodenum (P = 0.001), jejunum (P = 0.001), and ileum (P = 0.001), weights of the rumen (P < 0.001), duodenum (P = 0.001), jejunum (P < 0.001), and ileum (P < 0.001) of kids in ER, PR, and EPR were still less than those of kids in CON; N concentrations of rumen epithelium of kids in PR (P = 0.01) and EPR (P = 0.001), and the ratio of N to DNA of jejunum mucosa of kids in EPR (P < 0.001) were greater than those of kids in CON. Results indicate that nutritional restriction of 6 wk can retard gastrointestinal morphological development for kids weaned at 28 d of age and retarded development remains evident, even after nutritional recovery of 9 wk.

The effects of dietary phosphorus (P) variation on nutrient digestion, endogenous loss and plasma parameters were investigated in sixteen Liuyang black wether goats (8 months of age and average BW of 15 ± 0.25 kg) using a completely randomized design. The factors were phosphorus deficient in diet (1.41 g/kg DM, PDD) and phosphorus adequate in diet (PAD1.59, 1.77 and 1.92 g/kg DM, PAD1, PAD2 and PAD3). The results showed that increasing dietary P content increased the duodenal flow of dry matter (DM) (P 0.05) on apparent digestibility of DM, OM and nitrogen (N) digestion. Intestinal P digestibility linearly decreased (P 0.05) was noted in fecal endogenous P loss, which ranged from 0.767 to 0.884 g/kg DMI or 0.372 to 0.473 g/d, and true dietary P digestibility, which ranged from 42.9 to 51.2%, for PDD and PAD, but the proportion of endogenous P in feces tended (P 0.05) in plasma Calcitonin (CT), fibroblast growth factor 2,3 (FGF2,3), Parathormone (PTH), Thyroxine (T4), Ca and 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) concentrations. These results indicated that slight deficiency of dietary P had no significant effects on nutrient digestion. Insulin may be a regulator in phosphate absorption or re-absorption by ruminants.