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The mobile nylon bag technique (MNBT) may offer a simple, rapid means for assessing ileal AA digestibility of pig feed ingredients. In the present study, the effects of washing bags recovered from digesta, the amount and fineness of feeds, and feed trypsin inhibitor activity on apparent ileal digestibilities (AID) of CP and AA were determined with the MNBT. Twenty-four ileorectal anastomosed pigs (Yorkshire x Chinese Black barrows, 30 kg initial BW), of which 12 were fitted with duodenal T-cannulas, were used. Not washing the bags recovered from ileal digesta resulted in a reduction (P < 0.05) in apparent ileal digestibilities of CP and AA determined by MNBT. Washing the bags for more than 4 min overestimated (P < 0.05) the apparent ileal digestibilities of CP and AA compared with those determined with the anastomosed pigs. Sample size and fineness of grinding also affected (P < 0.05) apparent ileal digestibilities of CP determined by MNBT. The apparent ileal digestibilities of CP determined by MNBT were reduced (P < 0.05) when sample size exceeded 0.75 g and when feed was ground through screens with a mesh size of more than 1.0 mm. The closest agreement between results obtained by MNBT and a conventional ileal digestibility assay occurred when 0.75 g of feed ground through a 1.0-mm mesh screen was used per bag and bags were washed for 2 min after retrieval from digesta. Further studies are warranted to investigate the use of the mobile nylon bag technique for predicting the ileal digestibilty of AA for feeds containing antinutritional factors. Key Words: Amino Acids, Digestibility, Pigs

Polyamines are essential for the proliferation and differentiation of the rapidly renewing intestinal mucosa. The object of this study was to investigate polyamine metabolic profiles in the intestinal mucosa of piglets during the suckling and postweaning periods and under treatment with proline. Intestinal mucosa samples were obtained from 1-, 7-, 14-, and 21-d-old suckling piglets and piglets on Days 1, 3, 5, and 7 postweaning at 14 d of age, as well as from piglets that received the oral administration of proline from Day 1 to 14. During the suckling period from Day 1 to 21, higher concentrations of spermine and tyramine in the jejunal mucosa and putrescine, spermidine, and tyramine in the colonic mucosa were observed on postnatal Day 1 compared with other days (P < 0.05). Weaning at age 14 d induced an increase in the contents of tyramine in the jejunal mucosa and of spermine in the colonic mucosa but a decrease in 1,7-hepthyl diamine in the colonic mucosa on Days 1, 3, and 5 postweaning (P < 0.05). The mRNA and protein expression of ornithine decarboxylase (ODC) in three segments of the intestine were increased from Day 1 to 21, and a sharp increase was observed on Day 3 postweaning (P < 0.05). Oral administration of proline increased the concentrations of spermidine and spermine in the ileal mucosa and ODC protein expression in the three segments of the intestine (P < 0.05). These findings indicated that polyamine metabolism and ODC expression were altered by weaning and proline administration and may be useful as a marker of intestinal growth and restitution. [ABSTRACT FROM AUTHOR]

This study was conducted to determine the effects of different dietary protein contents on jejunal epithelial cells along the crypt-villus axis in nursing piglets. A total of 54 crossbred weaned piglets were randomly assigned to 3 dietary groups (14%, 17%, or 20% CP diets). Six piglets were randomly selected from each treatment and killed for tissue sampling at 10, 25, and 45 d after weaning. Jejunal epithelial cells were sequentially isolated along the crypt-villus axis and yielded 3 "cell fractions" (upper villus, middle villus, and crypt cells), and amino acid contents and the mRNA expression of amino acid transporters and genes related to protein degradation in jejunal epithelial cells were measured. At 10 d after weaning, dietary supplementation with 17% CP significantly increased (P < 0.05) the contents of Tau, Gly, Glu, and Cys in the upper villus compared with 14% or 20% CP. At 25 d after weaning, the 14% CP group had greater (P < 0.05) contents of Glu, Gly, Ala, Thr, Ser, Leu, and Tyr in the upper villus and Thr, Ala, Val, Ile, Tyr, and Lys in the middle villus compared with the 17% or 20% CP group. There was a similar response to feeding 14% low CP content with age, in which there was upregulation in expression, which occurred as early as 10 d postweaning for some genes (L amino acid transporter 1 [LAT1] in the middle villus and excitatory amino acid carrier 1 [EAAC1] in crypt cells) and at 25d postweaning for others (peptide transporter 1 [PEPT1] in the upper villus, B0 neutral amino acid transporter [B0,+AT1] in middle villus and Y+LAT1 in crypt cells). However, the mRNA expression of cationic amino acid transporter 1 (CAT1) in the upper villus and CAT2 in the middle villus was highest (P < 0.05) in the 17% CP group compared with the 14% and 20% CP groups at 10 d after weaning. In addition, the mRNA expression of LAT2 in the middle villus was highest (P < 0.05) in the 17% CP group compared with the 14% and 20% CP groups at 25 d after weaning. The PEPT1 mRNA in the middle villus of the 17% and 20% CP groups was greater (P < 0.05) than that in the 14% CP group at 45 d after weaning. The present study showed that the different CP content levels differentially affected the amino acid content and mRNA expression of the amino acid transporter in enterocytes along the crypt-villus axis and may help identify optimal CP contents in diets for nursery piglets. [ABSTRACT FROM AUTHOR]

Overweight and obesity are growing global health problems. Recently, gut microbiota was found to affect energy balance by determining the efficiency of calories obtained from the diet and how that energy is utilized and stored. This study was conducted to compare the differences in colonic microbiota and their metabolites situated within the colon of two genotype pigs fed with diets formulated to meet NRC nutrient requirements. Forty-eight barrows, including 24 Bama mini-pigs (a fatty-type Chinese local pig strain) and 24 Landrace pigs (a lean-type pig strain), were fed individually from 5 wk of age to market weight. Colon tissue and its content were sampled (n = 8) at nursery, growing, and finishing phases according to their individual physiological stage. Results showed that the abundance of colon luminal bacteria, including Bifidobacterium, Lactobacillus, Clostridium coccoides-Eubacteria rectal, Faecalibacterium prausnitzii, Prevotella, Escherichia coli, and Pseudomonas aeruginosa, was greater (P < 0.05) in Bama mini-pigs compared with Landrace pigs. The colon luminal concentrations of bacteria metabolites, including short-chain fatty acids (SCFAs), polyamine, indole, and skatole, were lower (P < 0.05) in Bama mini-pigs compared with Landrace pigs. Moreover, the colon tissue of Bama mini-pigs also showed higher inflammation status and worse epithelial barrier function than that of Landrace pigs. These results suggest that the SCFA-producing bacteria may be the bacteria responsible for the obesity and the lipopolysaccharide-containing bacteria may be the bacteria responsible for the relatively terrible intestinal health status of Bama mini-pigs. [ABSTRACT FROM AUTHOR]

An experiment was conducted to determine the effects of supplemental phytase on apparent ileal digestibility (AID) and apparent total tract digestibility (ATTD) of nutrients and energy in camelina expellers (CE) fed to growing pigs. The diets were a corn-soybean meal-based basal diet formulated to meet NRC nutrient requirements for growing pigs, the basal diet with energy-, AA-, and P-yielding ingredients replaced by 20% of CE without or with 500 FTU/kg of Buttiauxella spp. phytase. All diets contained TiO2 (0.4%) as an indigestible marker, and component digestibility in CE was determined by the difference method. A total of 9 ileal cannulated barrows (33.3 kg) were fed the diets in a 2-period crossover design. Each period lasted 9 d: 5 d for acclimation to the diets, 2 d for fecal collection, and 2 d for ileal digesta collection. Camelina expellers fed with phytase had greater AID of CP (66% vs. 56%) due to greater (P < 0.05) AID of Arg, Cys, Pro, Ser, and Tyr relative to CE fed without phytase. The AID of GE (55% vs. 47%) and P (68% vs. 38%) was great (P < 0.01) in CE fed with phytase compared to CE fed without phytase. Phytase improved (P < 0.05) ATTD of GE, P, and ADF in CE. Specifically, the DE and P contents in CE fed with phytase were, respectively, greater by 447 kcal/kg DM and 3.0 g/kg DM, which translated to 17% and 107% improvement on energy and P, respectively, relative to CE fed without phytase. The addition of phytase to a diet containing CE increased digestibility of nutrients and energy presumably due to increased utilization of nutrients bound to phytate. [ABSTRACT FROM AUTHOR]

Few studies have reported the influence of diets with or without adequate L-Lys on intestinal nutrient transport in piglets. The objective of this study is to evaluate the effects of diets with or without L-Lys supplementation on lysine transport and permeability in intestinal epithelial tissue by using the Ussing chamber technique. Twenty-one 21-d-old piglets (Duroc x Landrace x Yorkshire) with an average BW of 6.5 kg were randomly divided into 3 groups: a zein diet plus 1.35% L-Lys (Zein+LYS group), a zein diet without L-Lys (Zein--LYS group), and a N-free diet (NF group). Intestinal samples were collected after a 21-d period of feeding. In the presence of the same concentrations of lysine or mannitol on the luminal side of the mucosa in a chamber, the transport concentration and permeability rate of lysine in the Zein+LYS group was the highest in the ileum and the jejunum (P < 0.05) and the transport concentration of lysine in the jejunum was greater than that in the ileum; however, changes in the short-circuit current in the NF group were greater than those in the other 2 groups (P < 0.05); however, the transepithelial resistance in the Zein+LYS group was the highest (P < 0.05). In conclusion, the results indicated that dietary L-Lys supplementation was conducive to improving the transport of lysine in the small intestine of piglets. [ABSTRACT FROM AUTHOR]

Branched-chain amino acids (BCAA), including leucine (Leu), isoleucine (Ile), and valine (Val), play key roles in protein metabolism. This study was conducted to investigate whether the dietary ratio of BCAA influences the growth performance and serum amino acid pool of the growing pigs. A total of 40 crossbred pigs (Large White x Landrace; 9.85 ± 0.35 kg) were chosen and fed one of the five isocaloric diets varying in Leu:Ile:Val. The positive control diet contained 20% crude protein (CP) with a Leu:Ile:Val ratio of 1:0.51:0.63 according to the recommendation; for the other diets, the CP level was reduced to 17%, and the Leu:Ile:Val ratios were 1:1:1, 1:0.75:0.75, 1:0.51:0.63, and 1:0.25:0.25, respectively. The total BCAA amount was equal in all treatments, and the content of Leu, Ile, and Val was altered according to the setting ratios. No significant difference was observed in the growth performance between the pigs fed 20% CP and 17% CP diets supplemented with BCAA (P > 0.05). However, different Leu:Ile:Val ratios could affect the final weight (P < 0.05), average daily gain (ADG; P < 0.05), and feed:gain ratio (P = 0.06) of the pigs fed 17% CP diet. The final weight and ADG of the pigs in the 1:0.75:0.75 (17% CP), 1:0.51:0.63 (17% CP), and 1:0.51:0.63 (20% CP) groups were higher than those in the 1:0.25:0.25 (17% CP) group. The feed:gain ratio of the pigs fed the 1:0.75:0.75 (17% CP) diet was lower than that of those fed the 1:1:1 (17% CP) diet. There was no difference in the average feed intake among the treatments. Moreover, the diets supplemented with varied BCAA ratios influenced certain serum amino acid concentrations (P < 0.05), including Ile, Val, cysteine, and α-amino-adipic acid. These results indicated that a low CP diet (17%) supplemented with BCAA could keep up with the growth performance of growing pigs receiving adequate dietary protein (20%). The optimal Leu:Ile:Val within the range from 1:0.25:0.25 to 1:0.75:0.75 could improve the growth performance and serum amino acid profile of growing pigs fed the low CP diet. [ABSTRACT FROM AUTHOR]

Cottonseed meal (CM) and rapeseed meal (RM) have been used as alternative protein sources in porcine feed, but their exact digestive regulation remains unclear. This study was conducted to determine the dynamic profiles of AA released from different nitrogen composited diets in the jejunum of pigs. Seventy-two pigs (19.3 kg BW) were randomly assigned into 4 groups (18 pigs per group) and fed diets containing corn and either fish meal (FM), soybean meal (SBM), CM, or RM with equivalent AA for 7 d. The digesta of the jejunum were collected at 1, 4, and 8 h after feeding. The hydrolysate AA of undigested protein (HAA), free AA (FAA), and peptide-bound AA (PAA) in the digesta were determined. The lowest HAA contents were observed in the FM and SBM groups at 4 h. High levels of FAA were released from the SBM diet, whereas low levels of FAA were released from the RM diet at 1 and 4 h after feeding. The concentration of PAA in the CM group was lower than those in the FM and SBM groups. These results showed that the SBM diet could be easily degraded to FAA and peptide, and the FM diet tended to be degraded to peptide in the jejunum. There were less FAA and PAA released from the CM and RM diets although dietary AA were balanced, but the RM diet released more FAA and PAA than the CM diet. [ABSTRACT FROM AUTHOR]

This study was conducted to determine the profiles of AA in different segments of the gastrointestinal tract of pigs fed with different nitrogen composited diets. Twenty-four pigs (19.5 kg BW) were randomly assigned into 4 groups (6 pigs per group) and fed diets containing corn and fish meal (FM), soybean meal (SBM), cottonseed meal (CM), or rapeseed meal (RM) with equivalent AA compositions for 7 d. The contents of the stomach, proximal jejunum, distal jejunum, and ileum were collected at 4 h after feeding. The hydrolysate AA of undigested protein, free AA (FAA), and peptide-bound AA (PAA) in the contents were determined. There were more FAA in the proximal jejunum of SBM protein diets treatment, whereas more peptides were obtained from FM protein diets in the stomach and ileum as well as from SBM protein diets in the distal jejunum. The concentrations of FAA in the proximal jejunum and ileum as well as PAA in the jejunum with RM were higher than those with CM. When all 4 treatments were considered together, whereas few FAA were in the stomach and then increased in the jejunum and ileum, PAA were distributed uniformly in the 4 segments. These results showed that the RM protein diet gave a relatively continuous release of hydrolysis products in the stomach and small intestine. And FM and SBM protein diets were superior to CM for the release of peptides and FAA in the proximal gastrointestinal tract. These results regarding the AA profiles in different segments of the gastrointestinal tract should help to provide some information for the application of CM and RM in pigs. [ABSTRACT FROM AUTHOR]

Recent in vivo work with growing pigs suggests that the small intestinal mucosa plays an important role in degrading dietary essential amino acids (EAA). This study was conducted to test the hypothesis that EAA are extensively catabolized by pig enterocytes. Jejunal enterocytes were isolated from ten 50-d-old pigs weaned at 21 d of age (5 barrows and 5 gilts). Cells were incubated at 37 oC for 45 min in 2-ml oxygenated (95% O2/5% CO2) Krebs-bicarbonate buffer (pH 7.4) containing 1% BSA, 5 mM glucose, and plasma concentrations of amino acids (Wu et al. J Nutr 127: 2342, 1997). The medium also contained one of the following L-amino acids at 0.5, 2, or 5 mM plus their L-[1-14C]- or L-[U-14C]-labeled tracers: His, Ile, Leu, Met, Phe, Lys, Thr, Trp, and Val, as well as 0 or 5 mM L-cycloserine (an inhibitor of transaminase). The use of [1-14C]- and [U-14C]-labeled amino acids allowed for quantification of the oxidation of their carboxyl carbons and remaining carbon skeletons (Wu et al. Int J Biochem 19: 937, 1987). Results indicate extensive transamination of all the three branched-chain amino acids (BCAA) in enterocytes, with their α-ketoacids undergoing limited oxidation by branched-chain α-ketoacid dehydrogenase or the Krebs cycle. BCAA degradation was markedly inhibited by L-cycloserine (P < 0.01). Rates of enterocyte BCAA catabolism did not differ (P > 0.05) between barrows and gilts. Oxidation of all other EAA was negligible in the cells from barrows or gilts. The lack of degradation of His, Met, Phe, Lys, Thr, and Trp was confirmed by HPLC analysis of amino acids in medium plus incubated cells. Collectively, our results demonstrate that BCAA are degraded substantially in pig enterocytes and that these cells are not the site for the extensive catabolism of His, Lys, Met, Phe, Thr, and Trp in the pig small intestine. Supported by funds from the Chinese Academy of Sciences, China NSF, and TAES. [ABSTRACT FROM AUTHOR]

There are marked decreases in both plasma cortisol concentrations and intestinal activity of N-acetylglutamate synthase (NAGS; a key enzyme in arginine synthesis) in piglets during the suckling period. This study was designed to test the hypothesis that cortisol may play an important role in regulating intestinal NAGS expression in sowreared piglets. Thirty-two 7-day-old suckling pigs were randomly assigned to one of four groups with seven animals each, and received intramuscular injections of vehicle solution (sesame oil) (control group), hydrocortisone-21-acetate (HYD) (25 mg/kg body wt), RU486 (10 mg/kg body wt) (a potent blocker of glucocorticoid receptors), or HYD plus RU486. During the entire experimental period, pigs were nursed by sows. At 14 days of age, pigs were sacrificed for preparation of jejunal enterocytes for measurements of synthesis of citrulline and arginine from glutamine and proline, mitochondrial activity of NAGS, and mitochondrial concentration of N-acetylglutamate (NAG), using established methodologies (Wu, Am J Physiol 272: G1382, 1997; Bush et al. J Nutr 132: 59, 2002). Cortsiol administration had no effect (P > 0.05) on body weight but increased (P < 0.05) jejunal weight and villus height, compared with the control group. The cortisol treatment enhanced 1) NAGS activity and prevented the postnatal decline in NAGS activity during the suckling period; 2) increased NAG concentration as well as citrulline and arginine synthesis from glutamine and proline in enterocytes (P < 0.01), in comparison with the control group. The stimulatory effects of cortisol on intestinal NAGS activity and arginine synthesis were abolished (P < 0.01) by co-administration of RU486. Our results indicate that cortisol treatment provides a novel and effective means to prevent the marked declines in intestinal NAGS expression and arginine synthesis in suckling piglets via a glucocorticoid receptor-mediated mechanism. Supported by funds from the Chinese Academy of Sciences, China NSF, and USDA. [ABSTRACT FROM AUTHOR]

The objective of this study was to determine the effect of dietary starch sources on the balance of glucose and amino acids across the portal-drained viscera (PDV) of growing pigs. Four Duroc×Landrance×Yolkshire cross-bred barrows (with an average body wt of 22.5 kg) were housed individually in stainless steel metabolism cages and trained to consume feed provided daily. After a 2-wk adaptation period, pigs were fitted with permanent catheters in the portal vein, mesenteric vein, and carotid artery. After a 13-d recovery period, pigs were assigned randomly into one of 4 treatment groups in a 4×4 Latin square design representing 4 cornstarch- and casein-based isocaloric and isonitrogenous diets containing 52.0% corn, 65.8% brown rice, 65.3% sticky rice, and 51.8% Hi-Maize 1043 (resistant starch). Pigs were fed 3 times daily at 07:30, 15:30 and 23:30 at a feeding level of >963 kJ DE/kg diet. Each diet was fed to the pig after a 6-d adaptation period. On d 7, blood samples were obtained simultaneously from the 3 catheters at 30 min prior to feeding and hourly for 8 h after feeding. Portal blood flow was measured using p-aminohippuric acid. Results showed that portal glucose absorption (expressed per 100 g feed intake) was lower (P < 0.05) for the resistantstarch diet compared with corn, stick rice and brown rice diets at all sampling times. In comparison with the corn diet, net portal glucose absorption was higher (P < 0.05) for the sticky rice and brown rice diets up to 4 h after feeding, but was reduced (P < 0.05) thereafter. Feeding the resistant-starch diet reduced (P < 0.05) the net portal absorption of total amino acids, particularly Pro, Leu, and Ile. The net appearance of total amino acids absorbed from the ileum differed (P < 0.05) among the treatment groups, and was 48.4, 63.8, 61.8, and 59.3%, respectively, for piglets fed the corn, brown rice, sticky rice, and resistant-starch diets. These findings indicate that dietary sources of starch affect intestinal absorption and metabolism of glucose and amino acids in growing pigs. Supported by funds from Chinese Academy of Sciences and China NSF. [ABSTRACT FROM AUTHOR]

The objectives of this study were to determine true phosphorus (P) digestibility and the gastrointestinal endogenous P outputs associated with brown rice at the ileal and the fecal levels in weanling pigs. Six Duroc x Large White x Landrace barrows, with an average initial BW 12.5 ± 0.6 kg, were fitted with a simple T-cannula at the distal ileum and fed six diets according to a 6 x 6 Latin square design. The diets were cornstarch-based and contained six levels of P (0.80, 1.36, 1.93, 2.49, 3.04 and 3.61 g/kg DMI) from brown rice. Chromic oxide (3.5 Nonruminant Nutrition: Dietary Influences in Nursery Pigs g/kg diet, on as-fed basis) was included as a digestibility marker. Each experimental period consisted of 9 d with 6-d adaptation and 3d collection of representative ileal digesta and fecal samples. True ileal and fecal P digestibility values and the ileal and fecal endogenous P outputs associated with brown rice were determined by the regression analysis technique. There were no differences (P > 0.05) in true P digestibility values (ileal, 57.7 ± 5.4 vs. fecal, 58.2 ± 5.9%, n = 36) and the endogenous P outputs (ileal, 0.812 ± 0.096 vs. fecal, 0.725 ± 0.083 g/kg DMI, n = 36) between the ileal and the fecal levels. In conclusion, about 58% of the total P in conventional brown rice is digested in weanling pigs. The large intestine does not play an role in the digestion and absorption of P associated with brown rice in the weanling pig. [ABSTRACT FROM AUTHOR]

Six Yorkshire x Landrace dry sows, with an average initial BW 200 kg and 5-7 parity, were housed individually and fed six diets (2 kg/d) according to a 6x6 Latin square design. The diets were soybean meal (SBM)-cornstarch-glucose based and contained six graded levels of Ca (1.58, 1.69, 1.94, 2.30, 2.88 and 3.65 g/kg DMI) and P (0.79, 1.91, 2.91, 4.04, 4.86 and 5.82 g/kg DMI). Chromic oxide (0.35%) was included in the diets as a digestibility marker. Each experimental period lasted 8 d with a 5-d adaptation and 3-d collection of fecal samples. True digestibility of Ca (27 ± 5.0%) and P (44.0 ± 4.5%) and the endogenous outputs of Ca (1.19 ± 0.12 g/kg DMI) and P (0.78 ± 0.17 g/kg DMI) associated with the solvent-extracted SBM for the sows were obtained by the simple linear regression analysis technique. In conclusion, Ca associated SBM was poorly digestible in sows. The endogenous fecal Ca output associated with SBM was relatively high in sows. [ABSTRACT FROM AUTHOR]

The arginine-family amino acids include glutamine, glutamate, aspartate, proline, ornithine, citrulline, and arginine. They can be inter-converted in mammals through inter-organ metabolism and cell-specific pathways, although the rates of their conversion vary greatly with precursors, species, developmental stages, and disease. Growing interests in these amino acids in nonruminant nutrition mainly arise from the emerging knowledge about: 1) their high concentrations in fetal and postnatal animals; 2) remarkable species-differences in their tissue-specific catabolism and synthesis; 3) their roles in regulating the metabolic processes essential for animal growth and development (e.g., fat metabolism, protein turnover, glucose homeostasis, nucleotide synthesis, and immune response) via the production of unique metabolites and signaling pathways; 4) their dietary supplementation as a practical, effective means to maintain tissue integrity, improve pregnancy outcomes, enhance animal growth, and optimize health; and 5) their role in reducing dietary protein content to minimize nitrogen excretion and environmental pollution. Recent examples for the beneficial application of the arginine-family amino acids to swine nutrition are: 1) preventing intestinal atrophy and improving growth performance in weanling pigs through dietary supplementation with glutamine; and 2) increasing growth performance in milk-fed piglets and finishing pigs as well as enhancing fetal survival and growth in gestating sows through dietary supplementation with arginine. Future holds great promise for the use of the arginine-family amino acids in increasing the efficiency of animal agriculture. Supported by grants from USDA/NRI, TAES, Texas Tech University, The Chinese Academy of Sciences, and China NSF. [ABSTRACT FROM AUTHOR]

This study was conducted to determine the effects of exogenous zinc-metallothionein (Zn-MT) on anti-oxidative function in pork meat. After feeding a corn- and soybean meal-based diet for two weeks, 48 pigs (Duroc×Landrace×Chinese Black Pig) were assigned randomly into one of four treatment groups (12 pigs/group). Pigs in group 1 were maintained under non-stress conditions, whereas pigs in groups 2, 3 and 4 were aggressively handled for 25 min to produce stress. Then, pigs in groups 1 (control group) and 2 (negative control group) received intramuscular administration of saline, while pigs in groups 3 (low dose group) and 4 (high dose group) received 0.8 and 1.6 mg rabbit liver Zn-MT per kg body weight, respectively. Pigs were slaughtered at 3 and 6 h post-injection. Zn-MT treatment increased (P<0.05) the activities of superoxide dismutase (SOD) and glutathione-peroxidase (GSH-PX) while decreasing the concentration of malondialdehyde (MDA) in the liver. These responses were greater (P < 0.05) at 6 h than at 3 h post Zn-MT injection. Zn-MT treatment increased (P < 0.05) hepatic SOD mRNA levels in a time- and dosedependent manner, and decreased (P < 0.05) blood activities of glutamate-pyruvate transaminase and lactate dehydrogenase (indicators of tissue integrity). Zn-MT administration decreased (P < 0.05) lactic acid concentrations, thereby increasing (P < 0.05) the pH and water-holding capacity of the meat. Collectively, our results indicate that intramuscular administration of Zn-MT to preslaughter-stressed pigs improves tissue anti-oxidative ability and pork quality. Supported by funds from the Chinese Academy of Sciences and China NSF. [ABSTRACT FROM AUTHOR]

The experiment was conducted to determine the effects of dietary supplementation with the Chinese herb on growth performance, diarrhea incidents, serum biochemical parameters, and tissue integrity in weanling piglets. Sixty pigs were weaned at 21 days of age, housed individually and assigned randomly into one of three treatment groups (20 pigs/group), representing the corn- and soybean meal-based diets supplemented with 0 (control) or 0.2% Chinese herb or 0.02% Colistin (an antibiotic). The genus and species of the herbs used in the study were Astragalus membranaceus (Fisch.) Bge.var.mongholicus (Bge) hsiao; Acanthopanax senticosus (Rupr. Et Maxim) Harms; Codonopsis pilosula (Franch.) Nann.; Crataegus pinnatifida Bge.; and Salvia miltiorrhiza Bge. Pigs had free access to diets and drinking water. Feed intake and BW were measured weekly. Blood samples were obtained randomly from 5 piglets of each treatment group at wks 1, 2, 3, and 4 post-weaning. Results indicated that dietary supplementation with the Chinese herb for 4 wks increased (P < 0.05) ADG by 18.8% (432.1 vs 363.8 g), did not affect (P > 0.05) F:G (1.57 vs 1.62), and reduced (P < 0.05) diarrhea incidence by 40% in piglets, when compared with the control group. Dietary supplementation with Colistin did not affect (P > 0.05) ADG (385.9 vs 363.8 g)and had no effect (P > 0.05) on F:G (1.67 vs 1.62). At wk 1, serum concentrations of triglycerides in the herb-supplemented piglets were lower (P < 0.05) than those in the control group. At wk 2, the activity of serum creatine kinase (an indicator of tissue integrity) was lower (P < 0.05) in the herbsupplemented piglets in comparison with the other two groups. At wk 4, the activity of stomach amylase in the herb-supplemented piglets was higher (P < 0.05) than in the control and Colistin-supplemented piglets. These findings suggest that the Chinese herbal formula is a highly effective and safe feed additive for improving growth performance, preventing diarrhea, and protecting tissue integrity in weanling piglets. Supported by funds from the Chinese Academy of Sciences and China NSF. [ABSTRACT FROM AUTHOR]

The objective of this study was to determine true phosphorus (P) digestibility and the gastrointestinal endogenous P output associated with corn and soybean meal (SBM)-based diets for weanling pigs by the substitution method. Twelve Yorkshire weanling barrows, with initial BW between 10 and 12 kg, were fed two diets according to a completely randomized block design. The diets were corn and SBM-based and contained two levels of P (0.74 and 0.53% on DM basis) with the lower P diet formulated by replacing corn and SBM with 29% cornstarch. Chromic oxide (3.0 g/kg diet, on as-fed basis) was included as a digestibility marker. Each experimental period consisted of 8 d with 10-d adaptation and 4-d collection of representative fecal samples. True fecal P digestibility (61.2 ± 7.7%, n = 6) and the fecal endogenous P output (0.534 ± 0.481 g/kg DMI, n = 12) associated with the diet were determined by the substitution method. In conclusion, true fecal P digestibility and the endogenous P output associated with test dietary mixtures can be determined by the substitution method with dietary P levels meeting or close to recommended dietary P requirement levels in pigs. [ABSTRACT FROM AUTHOR]