Nutrient digestibility and performance responses of growing pigs fed phytase- and xylanase-supplemented wheat-based diets

Three experiments were conducted to evaluate the effect of supplementing phytase and xylanase on nutrient digestibility and performance of growing pigs fed wheat-based diets. In Exp. 1, 10 diets were fed to 60 pigs from 20 to 60 kg of BW to determine the effect of combining phytase and xylanase on apparent total tract digestibility (ATTD) of nutrients and growth performance. The 10 diets included a positive control diet (PC; 0.23% available P; 0.60% Ca) and a negative control diet (NC; 0.16% available P; 0.50% Ca) supplemented with phytase at 0, 250, and 500 fytase units (FTU)/kg and xylanase at 0, 2,000, and 4,000 xylanase units (XU)/kg in a 3 x 3 factorial arrangement. In Exp. 2, 6 ileally cannulated barrows (initial BW = 35.1 kg) were fed 4 wheat-based diets in a 4 x 4 Latin square design, with 2 added columns to determine the effect of combining phytase and xylanase on apparent ileal digestibility (AID) of nutrients. The 4 diets were NC (same as that used in Exp. 1) or NC supplemented with phytase at 500 FTU/kg, xylanase at 4,000 XU/kg, or phytase at 500 FTU/kg plus xylanase at 4,000 XU/kg. In Exp. 3, 36 barrows (initial BW = 55.5 kg) were fed 4 diets based on prepelleted (at 80 degrees C) and crumpled wheat for 2 wk to determine the effect of phytase supplementation on ATTD of nutrients. The 4 diets fed were a PC (0.22% available P; 0.54% Ca) and a NC (0.13% available P; 0.43% Ca) alone or with phytase at 500 or 1,000 FTU/kg. All diets in the 3 experiments contained Cr(2)O(3) as an indigestible marker. No synergistic interactions were detected between phytase and xylanase on any of the response criteria measured in Exp. 1 or 2. There were no dietary effects on growth performance in Exp. 1. In Exp. 1, phytase at 250 FTU/kg increased the ATTD of P and Ca by 51 and 11% at 20 kg of BW or by 54 and 10% at 60 kg of BW, respectively, but increasing the level of phytase to 500 FTU/kg only increased (P < 0.05) ATTD of P at 20 kg of BW. In Exp. 2, phytase at 500 FTU/kg increased (P < 0.05) the AID of P and Ca by 21 and 12%, respectively. In Exp. 3, phytase at 500 FTU/kg improved (P < 0.05) ATTD of P by 36%, but had no further effect at 1,000 FTU/kg. Xylanase at 4,000 XU/kg improved (P < 0.05) AID of Lys, Leu, Phe, Thr, Gly, and Ser in Exp. 2. In conclusion, phytase and xylanase improved P and AA digestibilities, respectively, but no interaction between the 2 enzymes was noted.     

Feeding behavior of feedlot lambs fed diets containing levels of cassava wastewater

In this study, we evaluated the effects of including cassava wastewater in the diet on the feeding behavior of feedlot lambs in 35 male uncastrated Santa Inês × Dorper crossbred lambs at an approximate age of 3 months, with an average live weight of 20.0?±?3.4 kg. Diets were formulated with hay of cassava shoots (roughage) and a concentrate based on corn and soybean, with a roughage:concentrate ratio of 50:50, plus inclusion of cassava wastewater at the levels of 0, 12, 24, 36, or 48 g/kg of the total diet. Feeding behavior was evaluated between the 46th and 52nd days of the experiment. Increasing cassava wastewater levels in the diet reduced (P?<?0.05) the intakes (kg/day) of dry matter and neutral detergent fiber as well as the efficiency of rumination (g/cud and g/h) of dry matter and neutral detergent fiber. The other behavioral parameters were not affected by wastewater inclusion in the diet. Therefore, the inclusion of up to 48 g/kg of cassava wastewater on fresh matter of diets is not recommended for feedlot lambs.     

Nutrient utilization in lambs fed diets high in sodium or potassium

Twenty-four wether lambs averaging 47 kg were used to study the effects of dietary K and Na additions on metabolism of lambs. Lambs were randomly allotted to four treatments and fed 900 g/d of the following: control diet consisting of 50% ground tall fescue hay and 50% concentrate; K diet calculated to contain 4% K with K added as KCl; Na diet calculated to contain 4% Na with Na added as NaCl, and K-Na diet containing 2% K and 2% Na with K and Na added from the same sources as in the K and Na diets. Water intake and urine excretion were highest for lambs fed the Na diet. Dry matter (DM) and crude protein (CP) digestibilities were similar among treatments. The K-Na diet resulted in decreased (P less than .05) acid detergent fiber (ADF) digestibility compared with lambs fed the Na diet. Nitrogen (N) retention was highest (P less than .05) in lambs fed the K diet and lowest in those fed the Na diet. Rumen NH3-N was lower (P less than .05) in lambs fed the Na diet compared with controls. Rumen K at 2 and 6 h postfeeding was highest (P less than .05) and rumen Na at 6 h lowest (P less than .05) for lambs fed the K diet. Plasma K values at both sampling times were highest (P less than .05) in lambs fed the K diet. At 6 h postfeeding, plasma Mg was higher in control lambs compared with those fed the K-Na diet.(ABSTRACT TRUNCATED AT 250 WORDS)     

Relationship between feeding behavior and performance of feedlot steers fed barley-based diets

The relationship between feeding behavior and performance of 274 feedlot cattle was evaluated using Charolais cross steers from 2 consecutive years averaging 293 ± 41 kg for yr 1 (n = 115) and 349 ± 41 for yr 2 (n = 159). Steers were blocked by BW and assigned to 3 (yr 1) or 4 (yr 2) feedlot pens equipped with a radio frequency identification system (GrowSafe Systems). Each pen contained 5 feeding stalls that allowed individual animal access to a feed tub suspended on load cells. The system recorded animal identification, duration, and frequency of feedings as well as the amount of feed consumed during each visit. Daily variation in DMI (DVI), calculated as the absolute difference in DMI from one day to the next, as well as eating rate were determined for each steer. Barley-based diets were delivered to meet steer ad libitum intake over the 213- and 181-d feeding periods for yr 1 and 2 of the study, respectively. The backgrounding periods included the first 85 and 56 d of yr 1 and 2, respectively, in which steers were fed a 14 to 30% concentrate diet, whereas the finishing periods included the last 116 and 101 d of feeding in yr 1 and 2, respectively, with the diet consisting of 77.9% concentrate. Steers were weighed individually every 14 d. To relate feeding behavior to performance, steers were grouped by ADG and G:F and categorized as high, average, or low (based on 1 SD greater than and less than the mean). In the backgrounding and finishing periods of both years of the study, steers classified as having high ADG exhibited greater (P < 0.001) DVI than steers classified as having average or low ADG. Total daily DMI was also greater (P < 0.001) for steers in the high ADG group than those in the low ADG group. Overall, those steers with the greatest G:F also tended (P = 0.15) to have greater DVI than average or low G:F steers. Compared with average or low G:F steers, DMI by high G:F steers in both years of the study was less during backgrounding, finishing, and overall (P = 0.02). Bunk visits and bunk attendance duration were less frequent and shorter (P ≤ 0.01) overall for high compared with low G:F steers. In this study, steers with more variable eating patterns exhibited greater ADG and tended to have greater G:F, a finding that is contrary to industry perception.     

Nutrient and energy retention in weaned Iberian piglets fed diets with different protein concentrations

Fifty-eight purebred castrated male Iberian (IB) piglets (initial BW 9.9 ± 0.1 kg) were used in an experiment to determine the effect of dietary protein content (PC) and feeding level (FL) on the rates of BW gain, whole body protein deposition (PD), and energy utilization between 10 and 25 kg of BW using the serial slaughter method. Treatments followed a 4 × 2 factorial arrangement with 4 PC (201, 176, 149, and 123 g of CP/kg of DM) and 2 FL (0.95 and 0.70 × ad libitum) and 6 or 7 piglets per combination of treatments. All diets were formulated to have an optimal AA pattern. Six piglets were slaughtered at the start of the trial to estimate initial body composition. The experimental pigs were individually housed in an environmentally controlled room (27 ± 2°C) until they reached 25 kg of BW, when they were slaughtered and analyzed for body composition. Positive linear effects of dietary PC on ADG, G:F, and gain:ME intake were observed (P < 0.001). Piglets fed at the highest FL showed greater ADG, G:F, and gain:ME intake (P < 0.001). An average increase was estimated to be 38.0 g of gain/MJ of ME intake. Protein deposition increased linearly from 35.6 to 50.9 g/d with increasing dietary PC (P < 0.001). A daily increase was estimated to be 0.35 g of PD/g of CP intake. Although the maximal genetic potential for PD of the IB piglet was not attained, a maximal value of 59.9 g/d for whole-body PD was achieved when the diet provided 201 g of CP/kg of DM and was fed at 0.95 × ad libitum. Piglets on the highest FL deposited on average 39% more body protein (P < 0.001) than restricted piglets. An average value of 4.39 g increase in PD/MJ of ME intake was obtained for diets containing 201 and 176 g of CP/kg of DM. Maintenance energy requirements and net efficiency of utilization of ME for growth, calculated by linear regression of ME intake on body retained energy, were 427 kJ/kg of BW(0.75)·d(-1) and 0.552, respectively. The corresponding partial efficiencies of utilization of ME for protein and fat deposition were 0.378 and 0.672, respectively, considerably less than the accepted values for conventional pig breeds. Practical diets of the young IB piglet should contain at least 201 g of ideal CP/kg of DM.     

Effects of supplemental protein source and level of urea on intestinal amino acid supply and feedlot performance of lambs fed diets based on alkaline hydrogen peroxide-treated wheat straw.

Two experiments were conducted to determine the effects of supplemental CP source and level of urea on intestinal amino acid (AA) supply and feedlot performance of lambs fed diets based on alkaline hydrogen peroxide-treated wheat straw (AHPWS). In Exp. 1, five cannulated (ruminal, duodenal, and ileal) crossbred wethers (61 kg) were used in a 5 x 5 Latin square design. Treatments consisted of different sources of CP and included soybean meal (SBM), a combination of urea, distillers dried grains (DDG), and fish meal, each provided an equal portion of supplemental CP (UDF), and three levels of urea (17, 33, and 50% of supplemental CP) fed in combination with DDG (U17, U33, and U50). Organic matter and N digestibilities decreased (P less than .05) when lambs were fed U17 compared with those fed SBM. There were no differences (P greater than .05) in bacterial N or AA flows to the duodenum due to CP source despite large differences in ruminal NH3 N concentrations and lower ruminal OM digestion when lambs were fed U17. Duodenal nonbacterial N and AA flows were highest (P less than .05) in lambs fed U17 and UDF and lowest when lambs were fed U50 and SBM. Lysine concentration in duodenal digesta decreased with incremental increases in DDG. In Exp. 2, 30 individually penned ram lambs (33 kg) were allotted to five CP treatments in a randomized complete block design. Treatments were similar to those of Exp. 1, with the exception that U17 was replaced by a 14% CP diet with SBM as the supplemental CP source; all other diets were formulated to contain 12% CP. Lambs fed U50 had decreased (P less than .08) ADG and gain/feed compared with all other treatments, and lambs fed UDF had greater (P less than .05) ADG and gain/feed than lambs fed U33. It was concluded that 17% of the supplemental CP from urea seems adequate to maximize bacterial protein synthesis and that no more than 33% of the supplemental CP should be provided by urea in diets based on AHPWS. Feeding a combination of ruminally resistant protein sources with complementary AA profiles of lysine and methionine (UDF) may enhance quality of protein entering the duodenum and feedlot performance.     

Nutrient intake, digestibility, and blood metabolites of goats fed diets containing processed jatropha meal

This study was conducted to record the ideal source and level of alkali treatment to treat jatropha meal (JM) and to determine the effect of inclusion of variously processed JM (pJM) on nutrient intake, digestibility, blood metabolites and hormonal status in goats. The JM was treated with 10 g/kg sodium chloride and 5 g/kg calcium hydroxide. The content of phorbol ester and hemagglutination (HA) activity of JM and pJM were assessed. A feeding trial for 90 days was conducted in short-haired multipurpose goats (n?=?15; five per group). The experimental animals were offered oat (Avena sativa) straw ad libitum throughout the experimental period of 90 days. Each group was assigned to one of the three diets, viz. R₁—soybean meal, R₂—sodium chloride (10 g/kg dry matter, DM), and R₃—calcium hydroxide (5 g/kg DM), with pJM substituting 250 g/kg DM of crude protein (CP) of control (R₁). At the end of the feeding period, digestion trial of 7 days was conducted. Blood samples were collected at the end of the experimental period to assess the blood metabolites and hormonal status. The phorbol ester and HA activity were reduced considerably in pJM. The intake of DM, organic matter, CP, and nitrogen-free extract were comparable among all the groups. However, the intake of ether extract was significantly higher in pJM-fed groups. The hemoglobin, packed cell volume, serum urea, triiodothyronine and testosterone contents decreased in R₂ and R₃ as compared to R₁. Concentration of glucose and activity of serum glutamic pyruvic transaminase and lactate dehydrogenase increased (P?<?0.01) in goats fed pJM. It was concluded that phorbol ester content and HA activity markedly decreased by processing JM with sodium chloride and calcium hydroxide. However, they were not reduced to the levels of safe feeding, as reflected in unusual values of blood metabolites among the experimental animals.     

Nutrient mass balance and performance of feedlot cattle fed corn wet distillers grains plus solubles

Two experiments using 96 steers each were conducted to evaluate the effect of corn wet distillers grains plus solubles (WDGS) concentration on steer performance, N loss, and P mass balance. Feeding WDGS as an energy source instead of protein may increase N release into the environment but also the amount of N removed in the manure. Calves (BW = 294 ± 33 kg) were fed 167 d from November to May (WIN), and yearlings (BW = 373 ± 24 kg) were fed 133 d from June to October (SUM). Treatments consisted of 0, 15, and 30% dietary inclusion of WDGS (DM basis) replacing corn (CON, 15WDGS, 30WDGS, respectively). Basal diets consisted of high-moisture and dry-rolled corn fed at a 1:1 ratio, 7.5% alfalfa hay, 5% molasses, and 5% supplement (DM basis). The CON and 15WDGS diets were formulated to meet MP requirements, and 30WDGS exceeded MP requirements. Dry matter intake, ADG, and HCW increased linearly (P < 0.05) with WDGS concentration in the WIN, whereas DMI and ADG increased linearly (P < 0.10) in the SUM. Efficiency of BW gain was not different (P > 0.10) among treatments in either experiment. Nitrogen and P intake increased linearly (P < 0.01) with WDGS concentration in both experiments. Calculated retention of N and P increased linearly (P ≤ 0.05) with WDGS concentration in the WIN but not in the SUM (P > 0.10). Calculated excretion of N and P increased linearly (P < 0.01) with WDGS concentration in both experiments. Amount of N removed in the manure was not different (P = 0.26) among treatments in the WIN but increased linearly (P = 0.05) with WDGS concentration in the SUM. Amount of P and OM removed increased linearly (P ≤ 0.05) with WDGS concentration in both experiments. Amount of N lost (kg/steer) increased linearly (P < 0.05) with WDGS concentration in both experiments. Expressed as a percentage of N excretion, N volatilization rate (amount of N lost divided by N excretion) was not different (P > 0.30) among treatments and averaged 68.3 and 77.0 in the WIN and SUM, respectively. More N volatilized when WDGS were fed, but not all of the additional N excreted was volatilized. Regressing the amount of OM on the pen surface against manure N, 98% of the variability for manure N in the WIN and 92% in the SUM was accounted for. Feeding WDGS increased the total amount of N lost to volatilization; however, not all of the additional N excreted was lost because of an increase in the proportion of manure OM.     

Intake,digestibility, rumen protein synthesis,and growth performance of Malawi Zebu steers fed diets containing rangeland-based protein sources

Tropical Animal Health and Production - The study evaluated effects of feeding Malawi Zebu steers with diets containing baobab (Adansonia digitata) seed meal and white thorn tree (Vachellia...     

Growth, feed intake, carcass characteristics, and eating behavior of feedlot lambs fed high-concentrate diets containing soybean hulls

The objectives of this experiment were to determine the effects of replacing ground corn with soybean hulls (SH) in high-concentrate diets on the growth (56-d period), carcass characteristics, and eating behavior of feedlot lambs. Sixty-four Santa Inês ram lambs (18.3 ± 2.8 kg of BW and 69 ± 5 d of age) were assigned to a randomized complete block design experiment with 8 blocks and 4 diets. The control diet contained 10% coastcross (Cynodon sp.) hay, 70% corn, and no SH (SH0) in the dietary DM. In the remaining diets, SH replaced corn at the rate of 15 (SH15), 30 (SH30), or 45% (SH45) of the original corn concentration, resulting in 0, 10.5, 21.0, or 31.4% SH in the dietary DM. Dry matter intake increased linearly (P < 0.01) when SH replaced ground corn (1.0, 1.0, 1.1, and 1.1 kg/d for SH0, SH15, SH30, and SH45, respectively). There was no effect on ADG of lambs, with values of 276, 278, 282, and 287 g for SH0, SH15, SH30, and SH45, respectively. Feed efficiency decreased linearly (P < 0.01) with SH inclusion. Carcass measures were not affected by SH as a replacement for ground corn. Eating time, expressed as minutes per day and minutes per gram of NDF, showed a quadratic effect (P < 0.05), whereas no effect was observed when expressed as minutes per gram of DM. Rumination, in minutes per day, was not influenced by dietary SH inclusion, but a linear decrease (P < 0.01) was observed when this variable was expressed as minutes per gram of NDF. Soybean hulls can replace up to 45% of the ground corn (31.4% of SH in the dietary DM) in high-concentrate diets fed to feedlot lambs without negative effects on ADG and carcass measures. The linear decrease in feed efficiency (11.6% reduction from SH0 to SH45) suggests that optimal dietary SH inclusion rates should be dictated by the relative costs of SH and corn.     

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.     

Effect of high-oil corn on growth performance, diet digestibility, and energy content of finishing diets fed to beef cattle

Sixty crossbred beef steers (initial BW = 412 kg) were used in a 83-d finishing study to determine the effect of feeding dry rolled high-oil corn on performance and total-tract digestibility of finishing diets. Steers were allotted by weight to the following dietary treatments: 1) control corn (C; 82% normal corn, 12% triticale silage), 2) high-oil corn (HO; 82% high-oil corn, 12% silage), and 3) high-oil corn formulated to be isocaloric to C (ISO; 74% high-oil corn, 20% silage). Total lipid content was 4.9% (DM basis) for normal corn and 7.0% for high-oil corn. Steers were individually fed using electronic gates. Quantity of feed offered and refused was recorded daily. Fecal samples were collected on d 63 to 66 of the trial to determine digestibility. Chromic oxide was fed as an indigestible marker for 7 d before fecal collection began. Planned contrasts of HO vs C and ISO vs C were used to assess treatment differences. Dry matter intake was greater for steers fed C vs HO (P < 0.01) or C vs ISO (P < 0.01), but daily gain and feed efficiency were not affected (P > 0.05) by treatments. Digestibility of DM, OM, starch, and GE was greater (P < 0.05) for the HO diet than the C diet, but lipid digestibility did not differ among treatments (P > 0.05). The combined effect of greater GE content and digestibility resulted in greater (P < 0.01) DE content for the HO than for the C diet. Calculated DE of the corn was 8.3% greater (3.74 Mcal/kg; P < 0.01) for the HO diet and 6.5% greater (3.67 Mcal/kg; P < 0.01) for the ISO diet than the corn in the C diet (3.25 Mcal/kg). Dry matter and GE digestibility did not differ (P > 0.05) between the C and ISO diets. Steers consuming ISO had greater (P < 0.05) starch digestibility than steers fed the C diet. Although HO had higher DE, DE intake was similar (P > 0.05) for HO and C due to lower DMI for HO. These results indicate that available energy is greater from high-oil corn than from typical corn, but depressed voluntary feed intake prevented performance improvements and resulted in equal energy intakes between high-oil corn and typical corn diets.     

Plasma glucose concentrations and digestibility of dry matter, energy and crude protein in mature geldings fed wheat and oat-based diets

Eight mature stock horse geldings were used in two simultaneous 4×4 Latin square experiments to determine the effect of feeding graded levels of wheat and oats on post prandial glucose concentrations and digestibility of dry matter (DM), energy and crude protein (CP). Experimental concentrate diets consisted of 100 (W), 66 (WO), 33 (OW) and 0 (O) percent wheat with the balance as oats. Concentrate diets were fed in a 60:40 ratio with prairie grass hay at equal DM intakes across treatments. The digestibility of DM and energy was greatest for W (p<.05) as compared to OW and O. No significant differences were detected in total tract apparent protein digestibility. Plasma glucose concentrations were highest in geldings fed W (p<.05) beginning 90 min post feeding and remained elevated out to 4 h indicative of the higher starch content of wheat. No palatability or health problems associated with feeding of wheat were noted. These data indicate that wheat can successfully be included in rations for horses.     

Assessment of the metabolic,protein, energy,and liver profiles of lambs finished in a feedlot and receiving diets containing groundnut cake

Forty-five crossbred Dorper × Santa Inês lambs were selected to assess the effect of replacing soybean meal by groundnut cake metabolic profile and histopathological evaluation of the kidney and liver tissues. The animals were 5 months old on average with a 24.5?±?5.3 kg initial body weight which were maintained fed in feedlot with groundnut cake (0, 25, 50, 75, and 100 %) as the replacement for soybean meal. Confinement lasted 84 days, and on the last day, the animals were fasted and slaughtered. A completely randomized design with five treatments and nine repetitions was used. Blood samples were collected from the jugular vein of each animal to evaluate the metabolic, protein, energy, and liver profiles of lambs. No effect was observed on protein, energy, or enzymatic profiles, which remained within the normal range for sheep. A histopathological examination was performed, and no deleterious effects from groundnut cake were observed in the liver or kidney tissues. Groundnut cake as a replacement for soybean meal can be used as an alternative protein source up to 100 % because it does not affect the metabolic, protein, and energy profiles or the liver and kidney functions of the growing sheep for slaughter.     

Evaluation of xylanase and a fermentable xylo-oligosaccharide on performance and ileal digestibility of broiler chickens fed energy and amino acid deficient diets

The objective of this study was to evaluate the effect of a product consisting of a combination of xylanase and xylo-oligosaccharide (STBIO) on performance and ileal digestibility of broiler chickens fed energy and amino acid (AA) deficient diets. Day-old male Ross 308 broiler chicks were randomly allocated to 8 pens per treatment, with 25 chicks per pen. Treatments based on wheat-corn-soybean meal diets were arranged in a 3 × 2 factorial design: a positive control that met or exceeded nutrient recommendations (PC), a negative control diet with a 50 kcal/kg apparent metabolizable energy (AME) reduction (NC1) and NC1 with a 3% reduction in AA content (NC2), each with or without supplementation of 100 g/t of the STBIO. Body weight gain (BWG), feed intake, feed conversion ratio corrected for mortality (FCR) and the European production efficiency factor (EPEF) were recorded from 0 to 42 d. On d 42, ileal samples were collected to determine dry matter (DM), organic matter (OM), ash, protein and energy digestibility. A significant interaction was observed for BWG and feed intake (P < 0.001). The energy and AA reduction reduced (P < 0.05) BWG when compared to the PC. The effect of STBIO on BWG was greater in NC1 (+451 g/bird) than in NC2 (+314 g/bird) or PC (+176 g/bird) diets (P < 0.05), and that in NC2 with STBIO was equal to that in PC without STBIO, and that in NC1 with STBIO was equal to that in PC with STBIO. No interactions were observed on the EPEF or FCR; however, STBIO improved EPEF (P < 0.001) and FCR (P < 0.001) irrespective of the energy reduction or AA density. The intake of digestible DM, OM, ash and energy for the finisher period was increased with STBIO supplementation (P < 0.01). A significant interaction was observed for the intake of digestible protein. NC1 and NC2 reduced the intake of digestible protein; however, when STBIO was supplemented, it was improved in both diets to similar levels to the PC. The stimbiotic supplementation improved performance of broiler chickens fed all diets, particularly those deficient in AME and AA.     

饲养系统和日粮对羔羊屠宰性能和肌肉矿物质含量的影响

文章旨在探讨不同饲养系统和日粮对羔羊生长、屠宰性能及肌肉矿物质含量的影响。试验将平均体重为（13.97±0.55）kg的120只羔羊随机分为3组,每组4个重复,每个重复10只。T1组在室内饲喂基础浓缩料,每天补充100 g稻草,T2组在室内饲喂基础浓缩料,每天补充100 g稻草和锌硒复合矿物质（0.2 mg/d硒,50 mg/d锌）,T3组在室外放牧,除了采食苜蓿草外,每天额外补充100 g稻草和100 g燕麦。试验时间为9周。结果：T1和T2组羔羊的末重、日增重、半胴体重、下肢深度、下肢重量、眼肌面积、颈、胸肌、肾重量均显著高于T3组（P＜0.05）,但骨盆骨重量显著低于T3组（P＜0.05）。各处理组羔羊的可食用部分和骨盆肌肉重量无显著差异（P＞0.05）。T2组63 d羔羊血液硒含量较T1和T3组分别显著提高了19.83%和25.0%（P＜0.05）,血液锌含量较T1和T3组分别显著提高了31.71%和45.91%（P＜0.05）。T3组羔羊肌肉钙含量较T1和T2组分别显著提高了8.79%和5.37%（P＜0.05）。T2羔羊肌肉硒和锌含量较T1和T3组分别显著提高了41.18%、65.52%和38.19%、46.15%（P＜0.05）,T2和T3组羔羊肌肉钾含量较T1组分别显著提高了3.27%和4.28%（P＜0.05）。结论：在本试验条件下,放牧羔羊胴体的脂肪含量低于室内饲养的羔羊,室外放牧可以提高肌肉钙和钾含量,但肌肉硒含量降低。[关键词]饲养系统|羔羊|屠宰性能|矿物质