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.     

Metabolizable energy,nitrogen balance,and ileal digestibility of amino acids in quality protein maize for pigs

Background：To compare the nutritional value and digestibility of five quality protein maize（QPM） hybrids to that of white and yellow maize,two experiments were carried out in growing pigs.In experiment 1,the energy metabolizability and the nitrogen balance of growing pigs fed one of five QPM hybrid diets were compared against those of pigs fed white or yellow maize.In experiment 2,the apparent and standardized ileal digestibility（AID and SID,respectively） of proteins and amino acids from the five QPM hybrids were compared against those obtained from pigs fed white and yellow maize.In both experiments,the comparisons were conducted using contrasts.Results：The dry matter and nitrogen intakes were higher in the pigs fed the QPM hybrids（P 〈 0.05） than in the pigs fed white or yellow maize.Energy digestibility（P 〈 0.001） and metabolizability（P 〈 0.01） were higher in the pigs fed the white and yellow maize diets than in those fed the QPM diets.The AID of lysine was higher（P〈 0.01） in the QPM diets than in the white and yellow maize.The AIDs of leucine,isoleucine,valine,phenylalanine,and methionine were lower in the QPM diets than those of maize（white and yellow）（all P 〈 0.05）.Maize（white and yellow） had greater SIDs of leucine,isoleucine,valine,phenylalanine,glutamic acid,serine,alanine,tyrosine,and proline（P 〈 0.05）.Conclusions：Based on these results,it was concluded that QPM had a lower metabolizable energy content and a higher amount of digestible lysine than normal maize.     

中草药饲料添加剂防治断奶仔猪腹泻及对生长性能的影响

选用断奶后的仔猪72头随机分为3个组,试验1组、2组分别添加两种中草药饲料添加剂,添加量均为0.50%。结果表明：试验1组、2组与对照组相比,腹泻率分别降低了77.11%、70.54%;日增重分别提高了10.06%、6.69%,试验1组与对照组相比差异达到显著水平（P〈0.05）;饲料报酬,试验1、2组较对照组分别提高了14.88%、9.04%,试验1组与对照组相比差异达到极显著水平（P〈0.01）,试验2组与对照组相比差异达到显著水平（P〈0.05）。     

Metabolizable energy,nitrogen balance,and ileal digestibility of amino acids in quality protein maize for pigs

Background

To compare the nutritional value and digestibility of five quality protein maize (QPM) hybrids to that of white and yellow maize, two experiments were carried out in growing pigs. In experiment 1, the energy metabolizability and the nitrogen balance of growing pigs fed one of five QPM hybrid diets were compared against those of pigs fed white or yellow maize. In experiment 2, the apparent and standardized ileal digestibility (AID and SID, respectively) of proteins and amino acids from the five QPM hybrids were compared against those obtained from pigs fed white and yellow maize. In both experiments, the comparisons were conducted using contrasts.

Results

The dry matter and nitrogen intakes were higher in the pigs fed the QPM hybrids (P < 0.05) than in the pigs fed white or yellow maize. Energy digestibility (P < 0.001) and metabolizability (P < 0.01) were higher in the pigs fed the white and yellow maize diets than in those fed the QPM diets. The AID of lysine was higher (P < 0.01) in the QPM diets than in the white and yellow maize. The AIDs of leucine, isoleucine, valine, phenylalanine, and methionine were lower in the QPM diets than those of maize (white and yellow) (all P < 0.05). Maize (white and yellow) had greater SIDs of leucine, isoleucine, valine, phenylalanine, glutamic acid, serine, alanine, tyrosine, and proline (P < 0.05).

Conclusions

Based on these results, it was concluded that QPM had a lower metabolizable energy content and a higher amount of digestible lysine than normal maize.     

Growth performance and nitrogen metabolism in weaned pigs fed diets containing different sources of starch

This study was conducted to determine the performance and N metabolism in weaned pigs fed diets containing different sources of starch. Pigs were weaned at 28 days of age, and assigned randomly into 4 soybean meal-based diets containing different sources of starch: corn, brown rice, sticky rice, and Hi-Maize 1043 (resistant starch). There were 12 pigs per treatment group in the growth-performance trial. Additionally, a 4 × 4 Latin design was used for a nitrogen (N) balance study, with 5 days for each experimental period (n = 4). Average daily gains were 0.38, 0.34, 0.31, and 0.28 kg/day (P < 0.01), respectively, for pigs fed the corn, brown rice, sticky-rice, and Hi-Maize 1043 diets. Feed:gain ratios were 1.65, 1.78, 1.95, and 1.86 (P < 0.01), for the above 4 diets, respectively. Fecal N and urinary N excretion as well as the apparent fecal digestibility of crude protein in pigs fed the corn, brown rice, and sticky-rice diets were higher (P < 0.01) compared with pigs fed the Hi-Maize 1043 diet. Collectively, our results indicate that dietary sources of starch affected both growth performance and N utilization in weaned pigs.     

Growth performance,nutrient digestibility,and fecal microbial composition of weaned pigs fed multi-enzyme supplemented diets

A study determined the effects of supplementing corn-based diets for weaned pigs with multi-enzymes on growth performance, apparent total tract digestibility (ATTD) of nutrients, fecal score, and fecal microbial composition. A total of 132 pigs (initial body weight = 7.23 kg) that had been weaned at 21 d of age and fed a drug-free nursery diet for 7 d were housed in 33 pens of 4 barrows or gilts, blocked by body weight and gender, and fed 3 experimental diets at 11 pens per diet. The diets were corn-based diet without or with multi-enzyme A or B. Multi-enzyme A supplied 4,000 U of xylanase, 150 U of β-glucanase, 3,500 U of protease, and 1,500 U of amylase per kilogram of diet. Multi-enzyme B was the same as multi-enzyme A except that it supplied amylase at 150 U/kg, and that its source of amylase was different from that of multi-enzyme A. All diets contained phytase at 1,000 U/kg. The diets were fed for 35 d in 2 phases; phase 1 for the first 14 d and phase 2 for the last 21 d of the trial. Fecal score was determined daily during the first 7 d of the trial. Fecal samples were collected from rectum of 1 pig per pen on days 2, 7, 14, and 35 of the trial for determining bacterial composition. Also, fresh fecal samples were collected from each pen on days 41 and 42 to determine ATTD of nutrients. Multi-enzyme B increased (P < 0.05) average daily gain (ADG) for phases 1 and 2. For the overall study period, multi-enzyme B increased (P < 0.05) ADG from 262 to 313 g, and average daily feed intake (ADFI) from 419 to 504 g. Multi-enzyme A increased (P < 0.05) overall ADG from 262 to 290 g, but did not affect ADFI. Multi-enzyme A or B did not affect ATTD of gross energy, but increased (P < 0.05) the ATTD of ether extract from 30% to 36% or 37%, respectively. Multi-enzyme A did not affect fecal score; however, multi-enzyme B tended to decrease (P = 0.09) fecal score, implying that it tended to decrease diarrhea. Firmicutes were the most abundant phylum of fecal bacteria (its relative abundance ranged from 58% to 72%). Bacteroidetes and Actinobacteria were the 2nd and 3rd most abundant phyla of fecal bacteria. Neither multi-enzyme affected fecal bacterial composition. In conclusion, the addition of multi-enzyme A or B to phytase-supplemented corn-based diet for weaned pigs can improve their growth performance and fat digestibility. However, multi-enzyme B was more effective than multi-enzyme A in terms of improving the growth performance of weaned pigs fed corn-based diet.     

Growth performance,apparent digestibility,and N balance in Mongolian lambs and hoggs fed diets supplemented with a Chinese traditional herbal medicine complex

We evaluated the effects of dietary supplementation with Chinese traditional herbal medicine (CTHM) on the growth performance, apparent digestibility, and nitrogen balance in Mongolian lambs and hoggs. The CTHM used as a dietary supplement consisted of 30% pine needles, 20% mugwort, 40% garlic, and 10% Astragalus mongholicus on a dry matter (DM) basis. The basal diet was prepared from corn stover, corn grain, wheat bran, rapeseed meal, shell meal, dicalcium phosphate, salt, vitamin premix, and mineral premix. In total, 16 Mongolian lambs (20.75 kg initial body weight [BW]) and 16 hoggs (33.81 kg initial BW) were allocated randomly to one of two treatments, the basal diet without and with CTHM, with the group receiving CTHM fed 98.5% basal diet + 1.5% CTHM complex on a DM basis. Lamb and hogg growth trials showed that CTHM supplementation improved the final live weight, gain, and feed conversion ratio (p < 0.01). A digestibility trial showed that the diet with CTHM improved the digestibility of DM, organic matter (OM), crude protein (CP), and neutral detergent fiber in lambs and hoggs. Finally, CTHM supplementation decreased (p < 0.0001) fecal and urinary nitrogen and increased (p = 0.0004) nitrogen (N) retention. Overall, the addition of CTHM to the diets of lambs and hoggs has beneficial effects on growth.     

Effects of chitooligosaccharide supplementation on growth performance, nutrient digestibility, blood characteristics and immune responses after lipopolysaccharide challenge in weanling pigs

The objective of this study was to determine the effects of dietary supplementation with chitooligosaccharide (COS) on growth performance, nutrient digestibility, blood characteristics and immune response in lipopolysaccharide-challenged weanling pigs. A total of 90 crossbred weanling pigs (5.44 ± 0.50 kg BW) were employed in Exp. 1. The three dietary treatments were basal diets supplemented with 0, 2.5, and 5 g COS/kg, and fed for 28 d. Each treatment had 6 replications with 5 pigs per pen. Increasing the level of supplemental COS tended to linearly (P < 0.10) improve ADG and ADFI during phase 2 and overall period, while there were no differences in G:F. The linear improvement in the apparent DM (P < 0.05) and N (P < 0.10) digestibility in pigs fed COS supplemented diets was noticed. The tested blood characteristics were not influenced under non-challenge conditions. In Exp. 2, a total of 20 pigs (5.22 ± 0.31 kg BW) were initially assigned to two dietary treatments and fed basal diets supplemented with 0 or 0.5 g COS/kg for 28 d. At the end of d 28, half of the pigs in each treatment (n = 5) were injected i.p. with Escherichia coli lipopolysaccharide at a concentration of 100 μg/kg of BW. The other half of the pigs in each treatment were injected with sterile saline solution at a concentration of 100 μg/kg of BW. This arrangement resulted in a 2 × 2 factorial design with diet and LPS challenge as the main effects. Blood sample and rectal temperature data were collected at 0, 2, 4 and 12 h post-challenge. Rectal temperatures increased as the result of LPS injection at 4 and 12 h post-challenge (P < 0.05). Serum cortisol, IGF-1, and TNF-α concentration were also increased as the result of LPS challenge (P < 0.05). The COS treatments resulted in lower cortisol concentrations at 2 h and higher IGF-1 concentrations at 4 h post-challenge (P < 0.05). COS and LPS interactions were also observed on cortisol and IGF-1 when the COS effects were presented (P < 0.05). Haptoglobin concentrations remained unaffected throughout the challenge period. White blood cell counts were increased in the LPS-treated pigs at 2 and 4 h post-challenge (P < 0.01). Lymphocyte count was elevated at 2 h and reduced at 12 h post-challenge as the result of LPS challenge (P < 0.05). However, there were no COS main effects observed on lymphocyte count throughout the challenge period. The comparison between two LPS challenged treatments also indicated that COS treatment has beneficial effects on rectal temperature, cortisol and IGF-1 concentrations. In conclusion, dietary supplementation with COS had little effect on nutrient digestibility and inflammatory stress markers in weanling pigs.     

Growth performance and gut health of Escherichia coli–challenged weaned pigs fed canola meal-containing diet

An experiment was conducted to evaluate the effects of including canola meal (CM) in diets for weaning pigs challenged with a F18 strain of Escherichia coli on growth performance and gut health. A total of 36 individually housed weaned pigs (initial body weight [BW] = 6.22 kg) were randomly allotted to one of the three diets (12 pigs/diet). The three diets were corn–soybean meal (SBM)-based basal diet (control diet) and the basal diet with 0.3% zinc oxide, 0.2% chlortetracycline, and 0.2% tiamulin (antibiotic diet) or with 20% CM diet. The diets were fed in two phases: Phase 1: days 0 to 7 and Phase 2: days 7 to 20. All pigs were given an oral dose of 2 × 10⁹ CFU of F18 strain of E. coli on day 7. Fecal score was assessed daily throughout the trial. Dietary antibiotics increased (P < 0.05) overall average daily gain (ADG) and average daily feed intake (ADFI) compared by 48% and 47%, respectively. Dietary CM increased (P < 0.05) overall ADG and ADFI by 22% and 23%, respectively; but the ADG and ADFI values for CM-containing diet did not reach those for the antibiotics-containing diet. Dietary antibiotics reduced (P < 0.05) fecal score; however, dietary CM unaffected fecal score. Dietary antibiotics decreased (P < 0.05) liver weight per unit live BW by 16% at day 20, whereas dietary CM did not affect liver weight per unit live BW (29.2 vs. 28.6). Also, dietary antibiotics increased (P < 0.05) serum triiodothyronine and tetraiodothyronine levels for day 14, whereas dietary CM did not affect the serum level of these hormones. Dietary antibiotics reduced (P < 0.05) the number white blood cells and neutrophils by 38% and 43% at day 20, respectively, whereas dietary CM tended to reduce (P = 0.09) the number white blood cells by 19% at day 20. The number white blood cells for CM diet tended to be greater (P < 0.10) than that for antibiotics diet. The dietary antibiotics decreased (P < 0.05) the concentration of individual volatile fatty acids and hence of total volatile fatty acid in cecum by 61% at day 20, whereas dietary CM decreased (P < 0.05) cecal butyric acid concentration by 61% and tended to reduce (P < 0.10) total volatile fatty acid concentration by 30% at day 20. In conclusion, the dietary inclusion of 20% CM improved ADG and tended to reduce white blood cell counts. Thus, inclusion of CM in antibiotics-free corn-SBM-based diets for weaned pigs that are challenged with F18 strain of E. coli can result in their improved performance partly through a reduction of the inflammatory response.     

Responses of non-starch polysaccharide-degrading enzymes on digestibility and performance of growing pigs fed a diet based on corn, soya bean meal and Chinese double-low rapeseed meal

This study was conducted to investigate the effect of two distinct enzyme preparations on nutrients' digestibility and growth performance of growing pigs fed diets based on corn, soya bean meal and Chinese double-low rapeseed meal (DLRM). The two enzyme preparations were Enzyme R, a preparation extracted from fermentation of a non-GMO fungus Penicillum funiculosum, developed for multi-grain and multi-animal species; and Enzyme P, a xylanase preparation from Trichoderma longibrachiatum, for pigs fed corn-based diets only. Both enzymes were tested at 0, 0.25 and 0.50 g/kg feed using 70 crossbred male pigs (Large Yorkshire x Landrace) in five dietary treatments and seven replicates in each treatment, for growth period from 27 to 68 kg live weight in 49 days. Results showed that the supplementation of both enzymes (1) increased total-tract digestibility of dietary energy from 77.5% (control) to 81.4% (Enzyme R, p < 0.05) and 81.9% (Enzyme P, p < 0.05); of neutral detergent fibre from 41.0% (control) to 57.8% (Enzyme R, p < 0.05) and 60.0% (Enzyme P, p < 0.05); (2) improved average daily gain from 786 g (control) to 829 g (Enzyme R, p < 0.05) and 846 g (Enzyme P, p < 0.05); and numerical increases in feed intake from 1.96 kg/pig/day (control) to 2.01 (Enzyme R) and 2.00 (p > 0.05) and feed conversion ratio from 2.50 (control) to 2.42 (Enzyme R) and 2.36 (Enzyme P, p < 0.05); (3) there was a dose response but no significant differences were observed in enzyme efficacy between the two enzyme preparations. The present study demonstrated beneficial effects of applying xylanase-based enzymes to improve feeding values of pig diets based on corn, soya bean meal and DLRM.     

Effect of δ-aminolevulinic acid on growth performance, nutrient digestibility, blood parameters and the immune response of weanling pigs challenged with Escherichia coli lipopolysaccharide

This study investigated the effects of dietary δ-aminolevulinic acid (ALA) on growth performance, nutrient digestibility, blood parameters and whether ALA improved the immune response of weanling pigs challenged with Escherichia coli lipopolysaccharide (LPS). Eighty pigs (body weight = 7.21 ± 0.51 kg) were allotted to four dietary treatments, with four pens per treatment and five pigs per pen. Basal diets were supplemented with 0, 5, 10, and 15 mg/kg ALA (as-fed basis) and fed for 35 days. At the end of the feeding period, 10 pigs were selected from both the 0- and 10-mg/kg ALA treatment groups; five were injected i.p. with LPS (50 μg/kg BW) and the other five pigs with an equivalent amount of sterile saline, resulting a 2 × 2 factorial arrangement. Blood sample and rectal temperature data were collected at 0, 2, 4 and 12 h after challenge. Growth performance was not affected by dietary treatments over the total experimental period. However, dry matter (DM) and nitrogen (N) digestibility was improved in the 15-mg/kg ALA treatment group at day 35 (P < 0.05). Serum hemoglobin (Hb) and iron levels were also increased, with the 10-mg/kg ALA treatment showing the highest concentration (P < 0.05). On day 35, red (RBC) and white blood cell (WBC) counts were elevated, with the 5- and 10-mg/kg ALA treatments having the highest counts (P < 0.05). During challenge, LPS injection elevated rectal temperature at 2 and 4 h postchallenge (P < 0.05). Plasma cortisol concentration was also increased by LPS injection at 2 and 4 h postchallenge and an ALA-alleviating effect was evident at 2 h postchallenge (P < 0.01). Concentration of plasma insulin-like growth factor-I (IGF-I) was increased in the ALA-supplemented treatments at 2 h postchallenge (P < 0.05). LPS injection increased plasma tumor necrosis factor-α (TNF-α) concentrations at 2, 4 and 12 h (P < 0.01), while an ALA-alleviating effect was observed at 2 and 4 h postchallenge (P < 0.05 and P < 0.10, respectively). Challenge with LPS decreased WBC counts at 2 and 4 h postchallenge (P < 0.01). At 12 h postchallenge, RBC, WBC and lymphocyte counts were affected by LPS challenge, while an ALA effect was only observed on WBC count (P < 0.05). In conclusion, dietary supplementation of ALA in weanling pigs can improve DM and N digestibilities, and iron status and have a beneficial effect on the immune response during inflammatory challenge.     

Use of refined potato (Solanum tuberosum L. cv. Gogu valley) protein as an alternative to antibiotics in weanling pigs

This study investigates the use of refined potato protein (RPP) obtained from the potato (Solanum tuberosum) tubers of “Gogu valley” for their antimicrobial properties and its effects on growth performance, apparent nutrient digestibility and microbial populations in feces and large intestine of weanling pigs. Pigs (n = 280; Landrace × Yorkshire × Duroc; average initial body weight of 5.96 ± 0.66 kg; 23 ± 3 d of age) were allotted on the basis of their body weight and sex to five dietary treatments (each treatment comprised of 4 replicate pens with 14 pigs in each) in a randomized complete block design. The dietary treatments were: PC (positive control; basal diet + 150 ppm apramycin sulfate and 10 ppm colistin sulfate), and RPP (basal diet added with 0, 200, 400 and 600 ppm RPP). The RPP showed in vitro antimicrobial activity and at the concentration of 150 ppm inhibited the growth of tested microbes (Staphylococcus aureus, Salmonella choleraesuis, Salmonella gallinarum and Escherichia coli). Pigs fed with antibiotic diet showed better growth performance and had lower populations of total bacteria, coliforms and Staphylococcus spp. in the feces and large intestine when compared with pigs fed RPP diets. Increasing the levels of RPP in diets linearly improved performance and reduced the populations of total bacteria, coliforms and Staphylococcus spp. in feces and contents of colon and rectum. The apparent fecal digestibility of DM, CP and apparent ileal digestibility of amino acids did not differ among pigs fed antibiotic and RPP diets. These results suggest that antibiotics were more effective in improving the performance of pigs, while feeding of RPP also improved the performance and reduced the harmful microbes being more effective at higher levels. Thus at higher levels RPP obtained from the potato tubers of Gogu valley can be a potential replacement of antibiotics in the feed of weanling pigs.     

Growth performance and metabolic responses in barrows fed low-protein diets supplemented with essential amino acids

This study was conducted to determine the effect of supplementation with Lys, Met, Thr to low-protein diets on growth performance and metabolic responses in growing barrows. Seventy crossbred barrows (Duroc × Yorkshine), with an average initial body weight of 16 kg, were fed diets containing five crude protein (CP) levels (18.2, 16.5, 15.5, 14.5, and 13.6%) and 0.83% true ileal digestible lysine. On d 17 of the trial, all pigs were fitted with an indwelling jugular catheter for blood collection. On d 18 and 53, blood samples were obtained at 4 h post feeding. Reducing dietary CP concentration linearly decreased (P < 0.05) ADG, ADFI, feed efficiency, longissimus muscle area (LMA), and plasma concentrations of urea N and protein, while increasing backfat thickness linearly (P < 0.05). Pigs fed the 13.6% CP diet exhibited the poorest growth performance. On d 53, dietary CP affected plasma IGF-I (quadratic, P < 0.01) and leptin (linear, P < 0.01) concentrations. Plasma leptin levels were correlated positively with backfat thickness (r = 0.76, P < 0.05) and negatively with LMA (r = − 0.64, P < 0.01). There was a positive correlation between ADG and plasma IGF-I concentrations (r = 0.91, P < 0.05). Our results suggest that adequate provision of nonessential AA and all EAA is required for achieving maximum growth performance and reducing fat accretion in growing pigs fed low-CP diets.     

Nutrient utilization and manure P excretion in growing pigs fed corn-barley-soybean based diets supplemented with microbial phytase

The effect of high levels of microbial phytase supplementation in diets for growing pigs was studied in a 2‐week performance and nutrient digestibility trial involving 28 growing pigs weighing 16.4 ± 1.06 (mean ± SD) kg. Seven corn‐barley‐soybean meal‐based diets consisting of a positive control (PC) formulated to meet or exceed NRC nutrient requirements; a negative control (NC) with non‐phytate P reduced by 0.1% unit from NRC requirement and fed without or with 500 or 1000 U/kg; a doubled negative control (DNC) with no added inorganic P and fed without or with 2000 or 4000 U/kg. Chromic oxide was added as an indigestible marker and all diets were fed as mash. Pigs fed the PC diet had a higher P digestibility compared with those fed the NC (P < 0.02) and the DNC (P < 0.001) diets. Supplementing the NC diet with pyhtase tended to improve P digestibility (P < 0.10). However, addition of phytase to the DNC diet resulted in linear (P < 0.001) and quadratic (P < 0.03) increases in P digestibility with an overall improvement of 8% and 121% at 4000 phytase U/kg of diet, respectively, compared with the PC and DNC diets. Apparent total tract digestibility of N, OM and DM were higher (P < 0.05) in the PC diet compared with the DNC diet, but not the NC diet (P < 0.10). No effect of phytase addition to NC was observed on Ca, N, DM and OM digestibility. Phytase addition to the DNC diet resulted in a linear increase (P < 0.05) in N, DM and OM digestibility but not Ca. Increasing the levels of phytase supplementation in the NC and the DNC diets linearly decreased fecal P (P < 0.05) content by 45 and 42%, respectively. Adding phytase at 1000 or 4000 U/kg increased P retention (P < 0.05) by 14.3 or 15.6% units, respectively, compared with the PC diet. Urinary P excretion was higher in the group fed the PC diet compared with those fed the NC and DNC diets (P < 0.05). The results of this study show that complete removal of inorganic P from growing pig diets coupled with phytase supplementation improves digestibility and retention of P and N, thus reducing manure P excretion without any negative effect on pig performance.     

低蛋白饲粮添加植酸酶和非淀粉多糖酶对生长猪生长性能和养分排泄量的影响

试验旨在研究低蛋白质饲粮添加植酸酶和非淀粉多糖(NSP)酶对生长猪生长性能、养分排泄量的影响。54头平均初始体重为(41.92±2.6)kg的杜长大三元杂交猪分为3组,每组3个重复,每个重复6头猪。1组为对照组(饲粮粗蛋白质水平为17.4%),2、3组为试验组,2组在1组基础上,饲粮粗蛋白质水平降至14.3%、总磷水平降低0.1个百分点,添加植酸酶;3组在2组基础上添加NSP酶,试验期38 d。试验结果表明,2组的平均日增重、料重比比1组分别提高7.64%和1.94%(P0.05),其余各组间差异不显著(P0.05);粪N浓度2、3组比1组分别降低18.58%、23.01%(P0.05);粪P浓度2、3组比1组分别降低40.23%、39.08%(P0.01)。由此可见,将常规饲粮粗蛋白质水平降低3个百分点、总磷水平降低0.1个百分点,并添加植酸酶,能显著提高生长猪平均日增重,显著减少粪氮含量,极显著减少粪磷含量;在此基础上,继续添加NSP酶不影响生长猪生长性能和粪中养分含量。     

The effect of dietary lysine restriction during the grower phase and subsequent dietary lysine concentration during the realimentation phase on the performance, carcass characteristics and nitrogen balance of growing–finishing pigs

Two experiments (exp.) were conducted to determine the effect of dietary lysine restriction during the grower phase and subsequent dietary lysine concentration during realimentation on the performance, carcass characteristics and nitrogen (N) balance of growing–finishing pigs. Seventy-two pairs of crossbred [meatline sires × (Large White × Landrace) dams] pigs (36 pairs entire male, 36 pairs female) were used in a 2 × 4 factorial performance study (exp. 1, 35 to 96 kg). The two factors were Diet1 (two lysine levels: LO or HI, day (d) 0 to 35) and Diet2 (four lysine levels: LO, M1, M2 and HI, d36 to slaughter). A further 30 boars were used in a 2 × 3 factorial N-balance study (exp. 2, 31 to 42 kg; Diet1: LO or HI; Diet2: LO, M3 and HI). The crude protein (CP) and lysine contents of the five isoenergetic (14.0 MJ DE/kg) diets were: LO (139 g/kg CP, 8.1 g lysine/kg), M1 (162 g/kg CP, 9.7 g lysine/kg), M2 (190 g/kg CP, 11.4 g lysine/kg), M3 (180 g/kg CP, 10.7 g lysine/kg) and HI (217 g/kg CP, 13.1 g lysine/kg). Diets were based on barley, wheat and soyabean meal with added vitamins, minerals and amino acids. Ratios of amino acids relative to lysine were similar for all diets. From d0 to 35 in exp. 1, pigs fed LO had lower daily gains (ADG: 785 vs. 939 g/day; P < 0.001), daily lysine intakes (DLYIN: 14.4 vs. 22.6 g/day; P < 0.001) and poorer feed conversion ratios (FCR: 2.28 vs. 1.84 kg/kg; P < 0.001) than pigs fed HI. From d36 to slaughter, pigs initially fed LO had higher ADG than those initially fed HI (948 vs. 879 g/day; P < 0.01). However, from d0 to slaughter, pigs initially fed LO had lower ADG (868 g/day; P < 0.01) and DLYIN (19.1 g/day; P < 0.001) than those fed HI (913 g/day and 23.3 g/day respectively). There was a Diet1 × Diet2 interaction for FCR from d36 to slaughter and d0 to slaughter (P < 0.05). FCR of pigs previously fed LO improved with each increase in dietary lysine concentration up to 13.1 g/kg (HI), but improvement was only evident for lysine concentrations up to 11.4 g/kg (M2) for pigs previously fed HI. In exp. 2, Diet1 was fed for an initial 5-day collection period (after adjustment to crate; C1). Diet2 was then fed and immediately there were 2 successive 5-day collection periods (C2 and C3). A Diet1 × Time interaction (P < 0.001) indicated that although N retention (NRET) during C1 was lower for pigs fed LO, there was no difference during C2 and C3 in NRET of pigs initially fed either LO or HI (14.5 vs. 25.0 g/day; 23.2 vs. 23.0 g/day; 26.0 vs. 26.6 g/day, for C1, C2 and C3, respectively). However, a similar interaction indicates that although N excretion (NEX) was 23% lower for LO compared with HI pigs during C1, there was no residual reduction in NEX of pigs initially fed LO (P < 0.01: 8.9 vs. 11.6 g/day; 12.3 vs. 12.7 g/day; 13.8 vs. 14.0 g/day, for C1, C2 and C3, respectively). Exp. 1 indicated improved performance and an ability to respond positively to higher lysine concentrations during realimentation for previously restricted compared with unrestricted pigs, however, overall performance was reduced. However, exp. 2 indicated that although NRET of initially restricted pigs increased during realimentation, it did not surpass that of unrestricted pigs. This apparent discrepancy may have been due to the time period of the N balance study.     

Effects of phytonutrients on growth performance,antioxidative status,and energy utilization of broilers fed low energy diets

Two experiments were conducted to investigate the effects of phytonutrients (PN) on growth performance, antioxidant status, intestinal morphology, and nutrient utilization of birds fed low energy diets. In Exp. 1, a total of 1,440 one-day-old Ross 308 male broiler chickens were randomly divided into 3 treatment groups, with 16 replicates per treatment (48 pens; 30 birds per pen). Birds in treatment 1 were fed diets with normal energy content (NE). Birds in treatment 2 were fed NE diet but with 60 kcal removed (LE). Birds in treatment 3 were assigned to LE diet supplemented with PN (LE + PN). Results indicated that LE diet increased feed conversion ratio (FCR) compared with NE from d 1 to 38, while LE + PN diet prevented this response (P = 0.02). At d 26, birds in the LE + PN group had the highest ileal and jejunal villus height to crypt depth (VH:CD) ratio. At d 39, PN supplementation improved ileal and jejunal VH:CD ratio, compared with LE group. Moreover, birds fed PN diets received a better economic profit. In Exp. 2, 360 one-day-old Ross 308 male broiler chickens were used in a metabolism study. The treatments used in Exp. 2 were the same as those in Exp.1, with 4 replicates (pens) and 30 birds in each replicate. Dietary apparent metabolism energy (AME), energy and protein digestibility were determined between 21 and 28 d of age. Results showed that chickens fed LE + PN diet tended to have greater AME (P = 0.02) and nitrogen-corrected apparent metabolism energy (AMEn) (P = 0.03) than birds fed LE diets. It was concluded that LE + PN showed a potential advantage to improve feed conversion and gut health of broilers, as well as economic profits.     

Nutrient digestibility, faecal physicochemical characteristics and bacterial glycolytic activity of growing pigs fed a diet supplemented with oligofructose or trans-galactooligosaccharides

The effect of oligofructose (FOS) or trans-galactooligosaccharides (TOS) inclusion at 10 g/kg diet for growing pigs, at the expense of cornstarch (CON), on growth performance, nutrient digestibilities, and faecal physicochemical parameters was determined. In addition, concentration of volatile fatty acids (VFA) and bacterial -glucosidase, β-glucosidase, β-galactosidase and β-glucuronidase activities in faeces were determined as markers of intestinal microflora metabolic activity. Twelve 35-day-old castrated pigs were allocated to CON, FOS and TOS dietary treatments for an experimental period of 4 weeks. Dietary treatments did not affect animal growth performance. FOS and TOS pigs tended to have a lower faecal output than CON pigs by approximately 6.0% and 1.7% respectively. FOS and TOS did not affect total tract apparent digestibility of dry matter, organic matter, fat, crude protein, crude fiber, ADF and cellulose. Digestibility of carbohydrate components such as nitrogen free extract and NDF was significantly (P ≤ 0.05) higher in TOS pigs compared to CON and FOS. Digestibility of hemicellulose in TOS pigs did not differ from FOS but was significantly higher from CON. The experimental period had a significant effect on most of the parameters determined. There were no significant (P ≤ 0.05) differences between treatments regarding total VFA concentration and faecal bacterial enzyme activities. Nevertheless, an increased saccharolytic activity in the gut of FOS and TOS pigs could be postulated by the trends for apparently higher VFA concentration and bacterial -glucosidase and β-galactosidase activities.     

多喂康对中大猪生长性能的影响

牛至香酚是多喂康的主要成分,能刺激动物的食欲,提高饲料转化率,从而改善动物的生长性能。通过在中大猪基础日粮中添加多喂康,研究多喂康对中大猪生长性能的影响。选取日龄、体重相近的中大猪338头,随机分成2组,其中对照组81头,试验组257头。结果表明,与对照组相比,试验组中大猪平均日增重提高85 g,日均采食量增加160 g,料重比降低0.14。说明在日粮中添加牛至香酚可以改善中大猪的生长性能。     

Comparison of growth performance and zinc absorption, retention, and excretion in weanling pigs fed diets supplemented with zinc-polysaccharide or zinc oxide

Fifty weanling crossbred pigs averaging 6.2 kg of initial BW and 21 d of age were used in a 5-wk experiment to evaluate lower dietary concentrations of an organic source of Zn as a Zn-polysaccharide (Zn-PS) compared with 2,000 ppm of inorganic Zn as ZnO, with growth performance, plasma concentrations of Zn and Cu, and Zn and Cu balance as the criteria. The pigs were fed individually in metabolism crates, and Zn and Cu balance were measured on individual pigs (10 replications per treatment) from d 22 to 26. The basal Phase 1 (d 0 to 14) and Phase 2 (d 14 to 35) diets contained 125 or 100 ppm added Zn as Zn sulfate, respectively, and met all nutrient requirements. Treatments were the basal Phase 1 and 2 diets supplemented with 0, 150, 300, or 450 ppm of Zn as Zn-PS or 2,000 ppm Zn as ZnO. Blood samples were collected from all pigs on d 7, 14, and 28. For pigs fed increasing Zn as Zn-PS, there were no linear or quadratic responses (P > or = 0.16) in ADG, ADFI, or G:F for Phases 1 or 2 or overall. For single degree of freedom treatment comparisons, Phase 1 ADG and G:F were greater (P < or = 0.05) for pigs fed 2,000 ppm Zn as ZnO than for pigs fed the control diet or the diet containing 150 ppm Zn as Zn-PS. For Phase 2 and overall, ADG and G:F for pigs fed the diets containing 300 or 450 ppm of Zn as Zn-PS did not differ (P > or = 0.29) from pigs fed the diet containing ZnO. Pigs fed the diet containing ZnO also had a greater Phase 2 (P < or = 0.10) and overall (P < or = 0.05) ADG and G:F than pigs fed the control diet. There were no differences (P > or = 0.46) in ADFI for any planned comparison. There were linear increases (P < 0.001) in the Zn excreted (mg/d) with increasing dietary Zn-PS. Pigs fed the diet containing ZnO absorbed, retained, and excreted more Zn (P < 0.001) than pigs fed the control diet or any of the diets containing Zn-PS. In conclusion, Phase 2 and overall growth performance by pigs fed diets containing 300 or 450 ppm Zn as Zn-PS did not differ from that of pigs fed 2,000 ppm Zn as ZnO; however, feeding 300 ppm Zn as Zn-PS decreased Zn excretion by 76% compared with feeding 2,000 ppm Zn as ZnO.