营养水平对鲁农2号配套系生长肥育猪生长性能以及养分消化率的影响

为探讨鲁农2号配套系生长肥育猪适宜的能量和粗蛋白质需要量,试验采用单因子随机区组设计,在保持消化能/粗蛋白质比不变的基础上,设为高能量粗蛋白质、中能量粗蛋白质和低能量粗蛋白质3个处理组。选取健康、初始体重（49.58±1.49）kg的鲁农2号配套系生长肥育猪108头（公母各半）随机分3个处理,每个处理4个重复,每个重复（圈）9头猪。试验分为50～80 kg和80～100 kg两个阶段。结果表明,试验全期饲粮营养水平的降低对猪日采食量、日增重和料重比影响不显著,但50～80 kg低营养水平组日增重和粗蛋白质日摄入量显著低于高、中营养水平组。养分表观消化率,50～80 kg以低营养水平组最高,与中营养水平组相比,其干物质、有机物、粗蛋白质和能量的表观消化率分别提高6.97%、8.53%、10.48%和6.45%,差异显著。饲粮营养水平对钙和磷的表观消化率均无显著影响（P〉0.05）。80～100 kg不同营养水平组养分表观消化率差异显著,其中,高营养水平组养分表观消化率最高,其干物质表观消化率分别比中、低营养组提高5.49%和7.17%（P〈0.05）;有机物的表观消化率分别提高4.48%和6.07%（P〈0.05）;钙的表观消化率分别提高32.76%和27.93%（P〈0.05）;磷的表观消化率分别提高38.77%（P〈0.05）和17.44%;粗蛋白质的表观消化率比中营养水平组提高8.56%（P〈0.05）。综合考虑,在50～80 kg阶段,鲁农2号配套系生长猪适宜的消化能为12.98 MJ/kg、粗蛋白质为14.56%;80～100 kg阶段,鲁农2号配套系肥育猪适宜的消化能为12.98 MJ/kg、粗蛋白质为12.40%。     

Effect of dietary L-carnitine on growth performance and body composition in nursery and growing-finishing pigs.

Two experiments were conducted to determine the effect of dietary L-carnitine on growth performance and carcass composition of nursery and growing-finishing pigs. In Exp. 1,216 weanling pigs (initially 4.9 kg and 19 to 23 d of age) were used in a 35-d growth trial. Pigs were blocked by weight in a randomized complete block design (six pigs per pen and six pens per treatment). Four barrows and four gilts were used to determine initial carcass composition. L-Carnitine replaced ground corn in the control diets to provide 250, 500, 750, 1,000, or 1,250 ppm. On d 35, three barrows and three gilts per treatment (one pig/block) were killed to provide carcass compositions. L-Carnitine had no effect (P > 0.10) on growth, percentages of carcass CP and lipid, or daily protein accretion. However, daily lipid accretion tended to decrease and then return to values similar to those for control pigs (quadratic P < 0.10) with increasing dietary L-carnitine. In Exp. 2, 96 crossbred pigs (initially 34.0 kg BW) were used to investigate the effect of increasing dietary L-carnitine in growing-finishing pigs. Pigs (48 barrows and 48 gilts) were blocked by weight and sex in a randomized complete block design (two pigs/pen and eight pens/treatment). Dietary L-carnitine replaced cornstarch in the control diet to provide 25, 50, 75, 100, and 125 ppm in grower (34 to 56.7 kg; 1.0% lysine) and finisher (56.7 to 103 kg; 0.80% lysine) diets. At 103 kg, one pig/pen was slaughtered, and standard carcass measurements were obtained. Dietary L-carnitine did not influence growth performance (P > 0.10). However, increasing dietary carnitine decreased average and tenth-rib back-fat (quadratic, P < 0.10 and 0.05), and increased percentage lean and daily CP accretion rate (quadratic, P < 0.05). Break point analysis projected the optimal dosage to be between 49 and 64 ppm of L-carnitine for these carcass traits. It is concluded that dietary carnitine fed during the nursery or growing-finishing phase had no effect on growth performance; however, feeding 49 to 64 ppm of L-carnitine during the growing-finishing phase increased CP accretion and decreased tenth-rib backfat.     

BGB饲料对生长猪和肥育猪生长性能的影响

本试验旨在评估BGB饲料对生长猪和肥育猪生长性能的影响。试验分两期进行,试验1选用初始体重为19.02±0.04kg的阉公猪72头,随机分为3组。以玉米-豆粕型日粮为基础日粮,对照组添加60mg/kg盐霉素,试验组分别添加5%、10%的BGB饲料。试验期28d,计算日采食量(ADFI)、日增重(ADG)和饲料转化率(FCR)。试验2选用初始体重为57.01±0.6kg的阉公猪54头,试验期35d,试验期日粮处理与饲养管理同试验1。试验1结果表明:处理组与对照组各项测定指标无显著差异(P>0.05),但在饲喂后期,5%BGB添加组的ADG比对照组提高7.8%,饲料转化率改善10.8%。试验2结果表明:处理组与对照组各项测定指标无显著差异(P>0.05),在饲喂后期,5%、10%BGB添加组的ADG分别比对照组改善了10.7%和4.0%。从全期结果来看,处理组的效果要优于对照组,5%BGB添加组效果最好。以上两个试验表明:添加BGB可以达到与添加抗生素相似的生产水平,对生长性能有一定的促进作用,最适添加量为5%。     

不同饲粮蛋白质水平对生长肥育猪生产性能的影响

蛋白质饲料是肉猪生产的重要物质基础,是决定生产成本的重要因素。为了探索饲粮蛋白质水平对生长肥育猪增重速度、饲料利用率及育肥猪肉品品质等的影响作用,确定肉猪合理的饲粮结构以获得更大的经济效益,进行了本试验。     

Effect of dietary crude protein level on growth performance,blood characteristics,and indicators of intestinal health in weanling pigs

An experiment was conducted to test the hypothesis that reducing crude protein (CP) in starter diets for pigs reduces post-weaning diarrhea and improves intestinal health. In total, 180 weanling pigs were allotted to 3 diets containing 22, 19, or 16% CP. Fecal scores were visually assessed every other day. Blood samples were collected from 1 pig per pen on days 1, 6, 13, 20, and 27, and 1 pig per pen was euthanized on day 12. Results indicated that reducing dietary CP reduced (P < 0.01) overall average daily gain, gain to feed ratio, final body weight, and fecal scores of pigs. Pigs fed the 16% CP diet had reduced (P < 0.01) serum albumin compared with pigs fed other diets. Blood urea nitrogen, haptoglobin, interleukin-1β, and interleukin-6 concentrations in serum were greatest (P < 0.01) on day 13, whereas tumor necrosis factor-α and interleukin-10 concentrations were greatest (P < 0.01) on day 6. Villus height in the jejunum increased (P < 0.05) and crypt depth in the ileum was reduced (P < 0.01) if the 19% CP diet was fed to pigs compared with the 22% CP diet. A reduction (P < 0.05) in mRNA abundance of interferon-γ, chemokine ligand 10, occludin, trefoil factor-2, trefoil factor-3, and mucin 2 was observed when pigs were fed diets with 16% CP. In conclusion, reducing CP in diets for weanling pigs reduces fecal score and expression of genes associated with inflammation.     

Assessment of chromium tripicolinate supplementation and dietary protein level on growth,carcass, and blood criteria in growing pigs

This study was conducted to evaluate potential interactive effects of supplemental Cr and dietary protein levels in growing pigs. Thirty-six individually penned barrows, 22 to 63 kg, were used in a 2 x 3 factorial arrangement of supplemental Cr (0 or 200 ppb from chromium tripicolinate) and protein level (76, 83, or 90% of lysine requirement). A corn-soybean meal basal diet was designed to supply all mineral and vitamin needs, 90% of the estimated metabolizable energy need, and 76% of the estimated protein need at 70% of ad libitum feed intake. Additional protein to 83 or 90% of the lysine requirement was provided by a soy protein isolate supplement. Growth data were collected for a 50-d period, and pigs were killed at a mean of 63 kg BW. Increasing lysine levels linearly (P < 0.01) increased ADG and liver weight. Lysine level had a quadratic effect on 10th rib backfat thickness (P < 0.05) and cooler shrink (P < 0.01) with the highest responses at the 83% lysine level. Increasing lysine level linearly decreased (P < 0.05) carcass content of ash and lipid and quadratically increased the carcass water content (P < 0.01). Carcass accretion rate showed a linear increase for protein (P < 0.01) and water accretion (P < 0.01). Dry matter composition of the longissimus muscle showed linear increases of ash (P < 0.05) and protein (P < 0.01) and a linear decrease of lipid content (P < 0.01) resulting in a linear increase (P < 0.05) of the protein to lipid ratio based on the increasing lysine levels. Pre-feeding insulin levels were increased (P < 0.05) with increasing level of lysine. One hour post-feeding, a quadratic lysine response for plasma glucose (P < 0.05) was observed with the lowest concentration at 83% lysine. Cr addition increased 10th rib backfat thickness (P < 0.10). There was no Cr x lysine level interaction (P > 0.10) observed for any of the growth or carcass traits. Plasma glucose concentrations pre-feeding were lower for Cr-supplemented pigs (P < 0.01). As expected, increasing protein levels in protein-deficient diets increased protein accretion while decreasing lipid accretion in 22 to 63 kg growing pigs; however, these effects were more clearly seen in the longissimus muscle than in the entire carcass. Supplementation of Cr exerted only minor effects with few Cr x lysine interactions observed in this study.     

Effect of dietary supplemental medium chain fatty acids instead of antibiotics on the growth performance,digestibility and blood profiles in growing pigs

Antibiotics have great functions in farm animal. However, the harm of antibiotics can't be ignored. The effects of medium‐chain fatty acids (MCFAs) supplementation to basal diet instead of antibiotics (CSP, Chlortetracycline, sulphonamide dimethazine and procaine penicillin, 1:1:1) on growth performance, nutrient digestibility and blood profile in growing pigs were studied. A total of 140 growing pigs (Landrace × Yorkshire × Duroc) with an average body weight of 27.84 ± 0.42 kg were allotted to four treatments of seven replicates/treatment and five pigs/replicate. The four experimental diets included: CON (basal diet, non‐antibiotic, negative control); CSP (CON + CSP 0.1%, positive control); M1 (CON + MCFA 0.15%) and M2 (CON + MCFA 0.3%). After 5 weeks, the fresh faecal and blood samples were collected from rectum and jugular vein respectively. The average daily gain (ADG) was significantly improved for pigs fed 0.3% MCFAs in relation to basal diet. Meanwhile, CSP supplementation had comparable effect on ADG. The lymphocyte percentage and IgG concentration were higher in blood of pigs‐fed MCFAs in relation to that of CON and CSP treatment while white blood cell and red blood cell were not affected. In relation to basal diet and CSP treatment, the digestibility of dry matter, nitrogen and gross energy (E) were unaffected with MCFAs supplementation. In conclusion, MCFAs improved growth performance on body weight gain and immune profile. Addition 0.3% MCFAs into the diet indicated that its partial positive effect as an alternative to antibiotic.     

Influences of dietary protein level,amino acid supplementation and environmental temperature on performance,body composition,organ weights and total heat production of growing pigs

The study was conducted to determine the effects of feeding a 16% CP diet, a 12% CP diet, or a 12% CP diet supplemented with crystalline Lys, Trp, and Thr (12% CP + AA diet) in a thermal-neutral (23 degrees C) or heat-stressed (33 degrees C) environment on various body and physiological measurements in growing pigs. Heat-stressed pigs were given a 15% lower daily feed allowance than thermal-neutral pigs to remove the confounding effect of feed intake caused by high temperature. No diet x temperature interaction was observed for any variables (P > 0.09) except for pig activity and pancreas weight. At 33 degrees C, pig activity and pancreas weight did not differ among dietary treatments (P > 0.05). In contrast, at 23 degrees C, pigs fed the 12% CP diet had greater activity than those fed the 16% CP diet or the 12% CP + AA diet (P < 0.05). Pancreas weight was greater for pigs fed the 12% CP + AA diet than those fed the 12% CP diet (P < 0.05) when maintained at 23 degrees C. Compared with 23 degrees C, the 33 degrees C temperature decreased pig activity, heat production, daily gain, feed efficiency, and affected the concentration and accretion of empty body protein and ash, as well as weights of heart, pancreas, stomach, and large intestine (P < 0.05). Pigs fed the 12% CP + AA diet attained similar levels of performance and rates of empty body water, protein, lipid, and ash deposition as pigs fed the 16% CP diet (P > 0.10). Pigs fed the 12% CP + AA diet had lower serum urea plus ammonia nitrogen concentrations (P < 0.01) and total heat production (P < 0.05) compared with those fed the 16% CP diet or the 12% CP diet. These results confirm that, with crystalline AA supplementation, growing pigs fed a 12% CP diet will perform similar to pigs fed a 16% CP diet. The data further indicate that lowering dietary CP and supplementing crystalline AA will decrease total heat production in growing pigs whether they are housed in a thermal-neutral or heat-stressed environment.     

Effect of protein level on performance,nitrogen utilisation and carcass composition in finisher pigs

Abstract

For 6 weeks, 256 female finisher pigs (initially 53.9 kg) were fed four dietary treatments of 136, 148, 159 and 168 g crude protein (CP)/kg diet. The latter diet was the 159 g CP/kg diet supplemented with dispensable amino acids, to study the effect of excess CP. Week 4 included use of metabolic cages. Feed intake, gain and feed utilisation were not significantly affected. Plasma urea (P < 0.001) and urinary nitrogen (P = 0.01) decreased linearly by lowering CP. The weight of the carcass tended to increase linearly by reducing CP, but neither nitrogen retention nor carcass meat percentage and back fat depth differed among treatments. In conclusion, the study indicated that CP could be decreased to 136 g/kg as-fed for growing pigs in the weight range 50–100 kg without negative impact on growth performance and carcass traits. Moreover, leanness was not affected by excess CP.     

乳酸菌发酵液体饲料对生长猪生长性能和粪中微生物区系的影响

<正>发酵液体饲料(Fermented liquid feed,FLF)作为一种新型饲料,最早使用是在20世纪80年代末的荷兰,当时的发酵液体饲料实际上就是湿拌料(陈文斌,2004)。随着现代饲料工业技术的发展,发酵液体饲料正朝着可人工控制发酵过程的方向发展(王金全,2009)。     

Effects of high-level dietary B-vitamins on performance, body composition and tissue vitamin contents of growing/finishing pigs

Forty-eight growing pigs were randomly assigned to five dietary groups and penned individually. They received a diet based on barley, wheat, corn and soya bean meal according to requirement. The experimental groups were supplemented with 400% or 800% of vitamins B(2), B(6) and pantothenic acid, or 400% or 800% of biotin, while all other vitamins were administered according to requirement. Growth performance, carcass characteristics, aspartate aminotransferase (AST), and content of vitamins in blood, liver and muscles were recorded. Growth performance showed no influence of supplementation, while backfat thickness in the group with 800% B(2)/B(6)/pantothenic acid was significantly higher. Content of B(2) in blood, liver and muscle was similar in all groups. Content of B(6) in blood and liver showed significant differences according to supplementation. The content of vitamin B(6) in muscle in the experimental groups was significantly higher than that in the control group. The content of pantothenic acid in blood and muscle in the experimental groups was significantly higher, while in liver all groups were significantly influenced by the supplementation level. Biotin content in liver showed no influence, but the content in plasma was significantly higher in the experimental groups and the content in muscle was significantly higher according to supplementation. The activity of AST showed no significant influence of the dietary vitamin level, but it was obviously decreased in the groups supplemented with biotin. The findings indicate that the dietary supplementation of vitamin B(2), B(6), pantothenic acid and biotin could not improve performance, but the contents in blood, liver and muscle.     

Effects of dietary iron level on growth performance,hematological status,and intestinal function in growing-finishing pigs

This study investigated the different addition levels of iron (Fe) in growing-finishing pigs and the effect of different Fe levels on growth performance, hematological status, intestinal barrier function, and intestinal digestion. A total of 1,200 barrows and gilts ([Large White × Landrace] × Duroc) with average initial body weight (BW; 27.74 ± 0.28 kg) were housed in 40 pens of 30 pigs per pen (gilts and barrows in half), blocked by BW and gender, and fed five experimental diets (eight replicate pens per diet). The five experimental diets were control diet (basal diet with no FeSO₄ supplementation), and the basal diet being supplemented with 150, 300, 450, or 600 mg/kg Fe as FeSO₄ diets. The trial lasted for 100 d and was divided into the growing phase (27 to 60 kg of BW) for the first 50 d and the finishing phase (61 to 100 kg of BW) for the last 50 d. The basal diet was formulated with an Fe-free trace mineral premix and contained 203.36 mg/kg total dietary Fe in the growing phase and 216.71 mg/kg in the finishing phase based on ingredient contributions. And at the end of the experiment, eight pigs (four barrows and four gilts) were randomly selected from each treatment (selected one pig per pen) for digesta, blood, and intestinal samples collection. The results showed that the average daily feed intake (P = 0.025), average daily gain (P = 0.020), and BW (P = 0.019) increased linearly in the finishing phase of pigs fed with the diets containing Fe. On the other hand, supplementation with different Fe levels in the diet significantly increased serum iron and transferrin saturation concentrations (P < 0.05), goblet cell numbers of duodenal villous (P < 0.001), and MUC4 mRNA expression (P < 0.05). The apparent ileal digestibility (AID) of amino acids (AA) for pigs in the 450 and 600 mg/kg Fe groups was greater (P < 0.05) than for pigs in the control group. In conclusion, dietary supplementation with 450 to 600 mg/kg Fe improved the growth performance of pigs by changing hematological status and by enhancing intestinal goblet cell differentiation and AID of AA.     

Effects of different levels of dietary protein with or without plant extract YGF251 on growth performance,nutrient digestibility,blood profiles,fecal microbial shedding,and fecal gas emission in growing pigs

This experiment was conducted to evaluate the effects of plant extract YGF251 supplementation in different protein level diets on growth performance, nutrient digestibility, blood profiles, fecal microbial shedding, and fecal gas emission in growing pigs. A total of 144 pigs (24.72 ± 1.54 kg) were randomly assigned to the treatments in a 2 × 3 factorial arrangement of dietary protein levels (15.50%, 14.00% or 12.50%) and plant extract YGF251 levels (0 or 0.05%) with 6 replications per treatment and 4 pigs per pen. Pigs fed low protein diets had reduced average daily gain (p < 0.05) and increased feed conversion ratio (p < 0.01) compared with pigs fed high protein diets. The apparent total tract digestibility of nitrogen was decreased (p < 0.05) when reducing dietary protein level. Fecal ammonia and hydrogen sulfide emissions were reduced (p < 0.05) when reducing dietary protein level. In conclusion, the results of the current study indicated that reducing dietary protein level impaired growth performance and nitrogen digestibility but reduced ammonia and hydrogen sulfide emissions in growing pigs. Dietary supplementation with 0.05% herbal extract YGF251 was not effective in improving growth performance, nutrient digestibility, or in decreasing gas emission in different protein diets.     

生长獭兔日粮中添加菊花对其生长性能、肉质性状和经济效益的影响

为了研究中草药菊花在生长獭兔上的应用效果,选取体重相似、身体健康的40日龄獭兔56只,随机分为4组,分别饲喂基础日粮、基础日粮+1%菊花、基础日粮+2%菊花和基础日粮+3%菊花。试验结束时分别对其生长性能、肉质性状和经济效益进行了分析。结果表明:生长獭兔中添加菊花各试验组平均日增重,分别比对照组提高15.8%、31.8%、24.4%,差异显著(P<0.05);平均采食量分别比对照组提高16.62%、20.3%、16.21%,差异显著(P<0.05)菊花有改善肉质颜色的作用,对肌肉pH值、嫩度亦有改善的趋势,但差异不显著(P>0.05);饲料中添加菊花能够显著提高经济效益。结论:菊花营养价值丰富兼有药物功效,可作为生长獭兔的良好添加物,结合生长性能、肉质性状和经济效益多方面因素,本研究认为2%添加水平最为适宜。     

Effects of dietary supplementation of modified zinc oxide on growth performance,nutrient digestibility,blood profiles,fecal microbial shedding and fecal score in weanling pigs

One hundred and forty piglets ((Landrace × Yorkshire) × Duroc, 21 day of age) with an initial weight of 6.50 ± 0.71 kg, were randomly allotted into four treatments to determine the effects of a modified form of zinc oxide (ZnO) on growth performance, nutrient digestibility, blood profiles, fecal microbial shedding and fecal score in weanling pigs. Dietary treatments were: (i) NC, negative control, basal diet containing zinc (Zn) from the premix; (ii) PC, positive control, basal diet containing Zn‐free premix + 3000 ppm ZnO; (iii) H1, basal diet containing Zn‐free premix + 3000 ppm ZnO (phase 1, days 1 to 14)/200 ppm modified ZnO (phase 2, days 15 to 42); (iv) H2, basal diet containing Zn‐free premix + 300 ppm modified ZnO (phase 1)/200 ppm modified ZnO (phase 2). During days 1 to 14, average daily gains (ADG) were higher (P = 0.04) in PC, H1 and H2 groups than that in NC group. Overall, H1 treatment increased the ADG compared with NC (P = 0.05). On day 14, the alkaline phosphatase and plasma Zn concentration were increased (P = 0.01 and 0.04, respectively) in PC, H1 and H2 treatments compared with NC treatment. On days 14 and 42, the fecal Lactobacillus counts in NC group were lowest (P = 0.01, P = 0.04 respectively) among treatments. All supplemented groups showed lower (P = 0.03) fecal score than NC treatment on days 21 and 28. In conclusion, dietary supplementation with modified ZnO increased growth rates and reduced fecal scores in weanling pig. Modified ZnO could be used as a substitute to ZnO as a growth promoter and reduce Zn excretion to the environment because of the lower dosage. [Correction added on 3 February 2015, after first online publication: the initial weight of ‘6.50 ± 1.11 kg’ has been replaced with ‘6.50 ± 0.71 kg’ in the abstract.]     

牛至油对育肥猪生长性能和肉品质的影响

文章旨在研究不同浓度的牛至油对肥育猪生长性能和肉质特性的影响。试验选择32头阉割公猪和32头后备母猪随机分成4个组,对照组饲喂基础日粮,试验组分别在基础日粮中添加0.2、0.4和0.8mg/kg牛至油,试验共开展5周。试验结束后禁食12h,称重后屠宰。经过一夜的冷却,从屠体上取50cm的腰肌(每组8头,4头公猪、4头母猪)。日粮中添加牛至精油对生长猪末重、日增重、屠宰率均无显著差异(P>0.05),同时各组最长肌嫩度、屠宰后45min和24h后的pH、肉色及感官特性也无显著差异(P>0.05)。此外,脂质氧化试验结果显示,日粮添加牛至油对肌肉无明显的抗氧化作用(P>0.05)。综上所述,由于胴体和肉质属性均无显著变化,说明本试验中日粮添加不同水平牛至油对猪的肉质参数没有影响。     

松针粉对生长猪生长性能及免疫功能的影响

为探究饲料中添加松针粉对生长猪生长性能及免疫功能的影响,选择品种、胎次相近,平均体重为(60.92±0.46)kg的杜×长×大(Duroc×Landrace×large white)三元杂交猪108头,按完全随机设计法分为3组,每组6个重复,每个重复6头猪,试验周期41 d。对照组饲喂基础日粮,试验A组饲喂基础日粮+2%松针粉(等量替代麸皮),试验B组饲喂基础日粮+2%松针粉(直接添加)。结果表明:与对照组相比,试验A组的日增重提高2.88%,采食量提高1.94%,料肉比降低3.91%(P > 0.05);试验组B日增重降低3.43%,采食量降低3.91%,料肉比降低 0.53%(P > 0.05);试验A组与B组的咳嗽率均有所降低,分别降低64.22%和53.43%(P > 0.05);试验A组与B组血清中免疫球蛋白IgG和IgM含量较高,但三个试验组之间差异不显著。因此,在饲料中用2%松针粉等量替代麸皮或直接添加2%松针粉均有提高猪只生长性能、降低咳嗽率、提高免疫功能的趋势(P > 0.05)。     

Assessment of chromium tripicolinate supplementation and dietary energy level and source on growth, carcass, and blood criteria in growing pigs

Two experiments were conducted to evaluate potential interactive effects of supplemental Cr and dietary energy supply in growing pigs. Experiment 1 used 36 individually penned barrows, 25 to 65 kg, in a 2 x 3 factorial arrangement of supplemental Cr (0 or 200 ppb) and energy level (70, 80, or 90% of ME requirement). A corn-soybean meal basal diet was designed to supply all protein, mineral, and vitamin needs and 70% of the estimated ME need at 70% of ad libitum feed intake. Additional energy to 80% or 90% of the ME requirement was provided by a cornstarch/corn oil blend. In Exp. 2, 30 individually penned barrows, 23 to 68 kg, were used in a 2 x 4 factorial arrangement of supplemental Cr (0 or 200 ppb) and added energy source (none, cornstarch, corn oil, or choice white grease) with basal diets identical to Exp. 1. The various energy sources were added to 90% of the ME requirement. In both experiments, growth data were collected over a 50-d period and pigs were killed at 70.1 kg. Increasing energy levels increased (linear, P < 0.01) ADG, average backfat thickness, 10th rib backfat thickness, and cooler shrink and decreased (linear, P < 0.01) longissimus muscle area in Exp. 1. Carcass composition increased (linear, P < 0.01) in lipid and decreased in protein, water, and protein:lipid ratio in response to increasing ME levels. Similar results were observed in Exp. 2 in response to added energy, regardless of the energy source used. In response to ME, linear increases (P < 0.05) in plasma insulin concentration before feeding and after feeding were observed in Exp. 1. In Exp. 2, plasma insulin concentration was lower for the basal diet before feeding (P < 0.05) and higher for the starch diet after feeding (P < 0.01); insulin:glucose ratio increased (P < 0.01) after feeding for starch compared to oil and fat. No consistent effect of Cr or Cr x ME level on performance or carcass was observed (P > 0.10) in these experiments. Similarly, no Cr effect or Cr x ME interaction (P > 0.10) was observed in plasma glucose or insulin levels. Dietary energy levels markedly affected growth criteria in growing pigs (23 to 68 kg) in these experiments, as anticipated, but supplemental Cr was without effect on performance or carcass responses.     

The effects of dietary fiber level on nutrient digestibility in growing pigs

The objective of this study was to investigate the effects of total dietary fiber level on nutrient digestibility and the relationship between apparent total tract digestibility of total dietary fiber, and soluble dietary fiber, insoluble dietary fiber and available energy. Sugar beet pulp was as the only fiber source. The experiment was designed as a 6 × 6 Latin square with an adaptation period of 7 d followed by a 5-d total collection of feces and urine. Feed intake tended to decrease (P =0.10) as total dietary fiber level increased. The apparent total tract digestibility of dry matter, crude protein and gross energy decreased (P <0.01) when total dietary fiber increased but the digestibility of soluble dietary fiber and insoluble dietary fiber increased (P <0.01). The digestible energy and metabolizable energy content of diets decreased (P <0.01) as the total dietary fiber increased.     

The effects of dietary fiber level on nutrient digestibility in growing pigs

The objective of this study was to investigate the effects of total dietary fiber level on nutrient digestibility and the relationship between apparent total tract digestibility of total dietary fiber, and soluble dietary fiber, insoluble dietary fiber and available energy. Sugar beet pulp was as the only fiber source. The experiment was designed as a 6 x 6 Latin square with an adaptation period of 7 d followed by a 5-d total collection of feces and urine. Feed intake tended to decrease （P =0.] O） as total dietary fiber level increased. The apparent total tract digestibility of dry matter, crude protein and gross energy decreased （P 〈0.0]） when total dietary fiber increased but the digestibility of soluble dietary fiber and insoluble dietary fiber increased （P 〈0.01）. The digestible energy and metabolizable energy content of diets decreased （P 〈0.01） as the total dietary fiber increased.