Influence of enzyme supplementation of diets and cooking–flaking of maize on digestive traits and growth performance of broilers from 1 to 21 days of age

A trial was conducted to study the influence of cooking–flaking (C-F) of maize and enzyme supplementation (ES) of the diet on mucosa morphometry, digestive organ weight, dietary component digestibility and growth performance of broilers from 1 to 21 days of age. There were 4 treatments arranged factorially with 2 heat processings of maize (raw and C-F) and 2 levels (0 and 500 mg/kg) of an enzyme complex with xylanase, protease and α-amylase activity. Dietary treatment did not affect any productive trait from 1 to 21 days of age. However, from 1 to 4 days of age, body weight gain (P<0.01) and feed conversion ratio (P<0.001) were improved by ES of the diet. Intestinal viscosity increased with C-F of maize and decreased with ES of the diet (P<0.001). The effects of ES on intestinal viscosity were more pronounced with C-F than with raw maize (P<0.001) and at younger than older ages (P<0.05). Cooking–flaking of maize increased total tract apparent digestibility of dry matter and organic matter (P<0.05) and of neutral detergent fibre and starch (P<0.001) and tended to improve ether extract (EE) digestibility (P<0.10). In addition, ES improved nitrogen retention (P<0.01) and EE digestibility (P<0.001). Digestibility of neutral detergent fibre and starch increased linearly (P<0.001) with age whereas nitrogen retention and organic matter, EE and gross energy digestibility decreased from 4 to 8 days of age and increased thereafter (P<0.001). The relative weight (g/kg body weight) of the pancreas decreased (P<0.01) and that of the liver increased (P<0.001) with C-F of maize. The relative weight of the proventriculus, gizzard and liver reached a maximum before 6 days of age and that of the small intestine and pancreas at approximately 7.8 days of age (P<0.001). Enzymes increased villus height (P<0.05) but did not affect villus width or villus surface area. It is concluded that C-F of maize improved dietary component digestibility but had no effect on broiler performance at 21 days of age. In addition, ES improved nitrogen retention, EE digestibility and productive performance of broilers but only from 1 to 4 days of age.     

Effects of dietary copper on growth performance, nutrient digestibility and fiber characteristics in cashmere goats during the cashmere slow-growing period

Thirty-six 2.5-year-old wether Inner Mongolian White Cashmere Goats (IMWG) (BW = 42.7 ± 3.44 kg) were used to determine the effects of dietary copper (Cu) concentration on growth performance, nutrient digestibility and fiber characteristics during the cashmere slow-growing period. Wethers were stratified by weight and randomly assigned to four dietary treatments, which included a control diet containing 5.60 mg Cu/kg DM, the control diet supplied, respectively, with 10, 20 and 30 mg Cu/kg DM (total dietary Cu level of 5.60, 15.6, 25.6 and 35.6 mg/kg DM). The experiment lasted 50 days including a 10-day preliminary trial and 10-day metabolism trial. Average daily feed intake (ADFI) did not differ among treatment groups (P > 0.05), except that the supplement providing 30 mg Cu/kg DM decreased average daily gain and gain efficiency (P < 0.05). Copper supplementation had no influence on digestibility of DM, CP and ADF (P > 0.05), however, NDF digestibility of the treatment group supplemented with 30 mg Cu/kg DM was lower compared with that of other groups (P < 0.05). Length and growth rate of cashmere fiber were higher in the treatment group supplemented with 20 mg Cu/kg DM compared with other groups (P < 0.05), but cashmere diameter was not affected by Cu supplementation (P > 0.05). In conclusion, supplementation of Cu at the levels of 10, 20 and 30 mg/kg DM to the basal diet containing 5.60 mg Cu/kg DM had no influence on ADFI or nutrient digestibility of DM, CP and ADF in cashmere goats, while 30 mg Cu/kg DM supplementation had a negative effect on growth performance and NDF digestibility. However, 20 mg Cu/kg DM supplementation of the basal diet enhanced cashmere growth. Hence, the appropriate supplemental level during the cashmere slow-growing period is deemed to be 20 mg Cu/kg DM (total dietary Cu level of 25.6 mg/kg DM).     

Effects of increasing crude protein concentrations on performance and carcass characteristics of growing and finishing steers and heifers

A 2 × 3 factorial design was utilized to ascertain the effects of three dietary crude protein (CP) concentrations on performance, carcass characteristics, and serum urea nitrogen (SUN) concentration in steers and heifers. Animals were blocked by gender (n = 9) and body weight (BW; n = 3/gender), randomly assigned to a diet containing 110, 125 or 140 g/kg dietary CP (n = 6), subjected to a growing period of 56, 84 or 112 d, depending on start BW, and a finishing period of 84 d. Animals were weighed and bled at 28 d intervals and daily dry matter intake (DMI), average daily gain (ADG), and gain to feed (G:F) were calculated and SUN was analyzed as a repeated measure throughout the study. Following slaughter, carcass data was collected for hot carcass weight (HCW), dressing percent (DP), kidney, pelvic and heart fat (KPH), 12th rib backfat (BF), loin muscle (LM) area, marbling score (MS), and yield grade (YG). Growing steers and heifers were programmed to gain 1.02 and 0.91 kg/d, respectively. Therefore, heifers consumed less than steers and steers gained more than heifers (P<0.01) with no differences in feed efficiency. Dietary CP treatment did not effect DMI, but did result in a quadratic (P=0.04) increase in ADG; thereby quadratically (P=0.06) and linearly (P=0.08) increasing final BW, and G:F, respectively. Finishing heifers consumed and gained less than steers (P<0.01), had lighter HCW (P<0.01) and greater DP (P=0.01) and LM area (P=0.01) than steers. DMI (P=0.02), ADG (P=0.05), HCW (P=0.08), and DP (P=0.06) reacted quadratically with increasing dietary CP. HCW (P=0.02) increased linearly with increasing dietary CP. G:F, KPH, BF, LM area, MS and YG was not affected by dietary CP concentration and G:F, KPH, BF, MS, and YG did not differ between genders. However, there was a gender × dietary CP interaction (P=0.01) for G:F. Steers were the most efficient at 125 g/kg dietary CP, while heifers were most efficient at 140 g/kg dietary CP. Gender had no effect on SUN concentrations, but SUN increased linearly (P<0.01) with increasing dietary CP concentrations. In conclusion, quadratic responses in DMI and ADG indicate that a 125 g/kg dietary CP concentration is optimal for either steers or heifers during the finishing period.     

Effects of groundnut stover or Bermudagrass hay supplementation to doe kids on winter hardwood range

Goats in north-central Texas raised on rangeland often face winter forage quantity and quality deficits that may be mitigated by feeding hay or stover. Groundnut (Arachis hypogea) stover (8% CP, 35% ADF, 43% NDF and 8% acid detergent lignin (ADL) DM basis) and bermudagrass (Cynodon dactylon) hay (12% CP, 33% ADF, 73% NDF, and 5% ADL DM basis) were tested at Stephenville, Texas as 0.0, 0.5, or 2.0% BW supplement/substitution diets on 18 kg Boer X Spanish doe kids browsing native hardwoods (8 ha⁻¹). Both hay and stover were fed ad libitum in a traditional feedlot, using a complete formulated feed ration as a control. Trials ran for 10 weeks from January to March in 2003 (134 mm rainfall) and in 2004 (182 mm rainfall). Goats receiving 0.5% and 2% BW bermudagrass or 2% BW groundnut stover had greater ADG than those in the control and 0.5% BW groundnut paddocks (P < 0.05). Goats fed complete ration in the drylot had greater (P < 0.05) ADG than those eating either hay or stover ad libitum. Bermudagrass hay rejected by goats in the hardwood trial was 20% lower in CP, 7% greater in NDF, 8% greater in ADF, and 9% greater in ADL than the original fed hay; groundnut stover refusals were 21% lower in CP, 12% greater in NDF, 19% greater in ADF, and 20% greater in ADL concentration than the stover when fed. Supplementing goats on hardwood range with bermudagrass hay or groundnut stover may improve ADG when browse is scarce or of poor quality.     

Growth performance and carcass characteristics of Awassi lambs and Shami goat kids fed yeast culture in their finishing diet

Two experiments were completed to examine effects of inclusion of a yeast culture (YC) to a diet based on barley grain and wheat straw on digestibility, growth and meat traits of Awassi lambs and Shami goat kids. Experiment 1 studied effects of YC on apparent digestibility of dry matter (DM), organic matter (OM), crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF) and N balance in sheep, while experiment 2 studied effects on growth performance and carcass composition of lambs and kids. The same diet was used in both experiments and the YC was added to the diet of treated groups at the level of 12.6 kg YC/tonne of diet. Addition of YC had no effect on apparent digestibility of DM, CP and NDF, but it increased (P<0.05) digestibility of OM and ADF. No differences occurred in N intake, output or retention. Addition of YC did not affect growth rate, or DM intake, in both lambs and kids. YC supplementation to lambs reduced hot carcass weight, cold dressing proportion and total muscle/bone ratio, but increased empty digestive tract weight. There were no changes in back fat thickness, intermuscular fat of the leg muscle, and weights and proportions of carcass cuts. Measures of kids’ carcass characteristics and quality also did not differ. Only cuts of leg and shoulder differed (P<0.05) when calculated as a proportion of the whole carcass cut. Results show that YC supplementation increased digestibility with no effect on growth, feed intake or feed conversion ratio of fattening lambs and kids. However, YC supplementation reduced meat/bone ratio and tissue protein content, but increased fat content in carcasses of fattening Awassi lambs, but not in fattened Shami kids.     

Effects of feeding high- and low-fibre fractions of air-classified,solvent-extracted canola meal on diet nutrient digestibility and growth performance of weaned pigs

The dietary energy value of solvent-extracted canola meal (CM) is limited by its relative high fibre content. The fibre-rich hull of canola is denser than the oil-free cotyledons, so these seed components partially fractionate in a stream of air. Air classification thus separates CM into a low-fibre, light-particle fraction and a high-fibre, heavy-particle fraction of interest for feeding monogastric and ruminant species, respectively. Crude fibre (CF), acid detergent fibre (ADF) and neutral detergent fibre (NDF) in light-particle fraction were reduced by 96, 34 and 28% compared with CM (83 CF, 165 ADF, 238 NDF g/kg, as-is). Brassica (B) napus, Brassica juncea, or their fractions were evaluated feeding 288 weaned pigs (7.1 kg) for 37 d as a 2 × 3 factorial with 12 replicate pens per treatment. Wheat-based diets including 200 g of test feedstuff/kg provided 10.5 and 10.0 MJ net energy (NE)/kg and 1.27 and 1.15 g standardised ileal digestible lysine/MJ NE and were fed for 9 and 28 d, respectively. Pen feed added, orts, and individual pig body weight were measured weekly to calculate average daily feed intake (ADFI), average daily gain (ADG), and feed efficiency (G:F). Pen faecal samples were collected on d 16 and 17 to calculate diet apparent total tract digestibility coefficients (CATTD) of dry matter (DM), gross energy (GE), crude protein (CP) and digestible energy (DE) value. Pigs fed B. juncea had 3 and 2% higher (P<0.001) CATTD of DM (0.82 vs. 0.79) and GE (0.84 vs. 0.82) than pigs fed B. napus. Feeding the light-particle fraction increased (P<0.001) CATTD of DM (0.82 vs. 0.79), GE (0.84 vs. 0.82), and CP (0.79 vs. 0.77) by 4, 3 and 3% compared with CM, respectively. For the entire trial, pigs fed B. juncea consumed 33 g/d less (P<0.001) feed (723 vs. 756 g/d), had 0.02 higher (P<0.05) G:F (0.735 vs. 0.718 g:g), but ADG (503 vs. 514 g/d) was not different (P>0.05) compared to pigs fed B. napus. Feeding pigs the light-particle fractions did not affect (P>0.05) ADFI (741 vs. 736 g/d), increased (P<0.05) G:F 0.02 (0.739 vs. 0.721 g:g) and tended to increase (P=0.07) ADG (519 vs. 501 g/d) by 18 g/d compared to CM. In conclusion, air classification of canola meal increased diet nutrient digestibility, but only modestly increased G:F of weaned pigs due to dietary fibre reduction.     

Effect of exercise on apparent total tract digestibility of nutrients and faecal recovery of ADL and TiO2 in ponies

Exercise and physical training are known to affect gastrointestinal function and digestibility in horses and can lead to inaccurate estimates of nutrient and energy digestibility when markers are used. The effect of exercise on apparent nutrient digestibility and faecal recoveries of ADL and TiO₂ was studied in six Welsh pony geldings subjected to either a low- (LI) or high-intensity (HI) exercise regime according to a cross-over design. Ponies performing LI exercise were walked once per day for 45 min in a horse walker (5 km/h) for 47 consecutive days. Ponies submitted to HI exercise were gradually trained for the same 47 days according a standardized protocol. Throughout the experiment, the ponies received a fixed level of feed and the daily rations consisted of 4.7 kg DM of grass hay and 0.95 kg DM of concentrate. The diet was supplemented with minerals, vitamins and TiO₂ (3.0 g Ti/day). Total tract digestibility of DM, organic matter (OM), CP, crude fat, NDF, ADF, starch, sugar and energy was determined with the total faeces collection (TFC) method. In addition, DM and OM digestibility was estimated using internal ADL and the externally supplemented Ti as markers. Urine was collected on the final 2 days of each experimental period. Exercise did not affect apparent digestibility of CP, crude fat, starch and sugar. Digestibility of DM (DMD), OM (OMD), ADF and NDF tended to be lower and DE was decreased when ponies received the HI exercise regime. For all treatments combined, mean faecal recoveries of ADL and Ti were 87.8±1.7% and 99.3±1.7%, respectively. Ti was not detected in the urine, indicating that intestinal integrity was maintained with exercise. Dry matter digestibility estimated with the TFC, ADL and Ti for ponies subjected to LI exercise were 66.3%, 60.3% and 64.8%, respectively, while DMD for HI ponies were 64.2%, 60.3% and 65.2%, respectively. In conclusion, physical exercise has an influence on the GE digestibility of the feed in ponies provided with equivalent levels of feed intake. In addition, the two markers used for estimating apparent DMD and OMD indicate that externally supplemented Ti is a suitable marker to determine digestibility of nutrients in horses performing exercise unlike dietary ADL.     

Effects of age and mannanoligosaccharides supplementation on production of volatile fatty acids in the caecum of rabbits

This trial studied the effect of including mannanoligosaccharides (MOS, Bio-Mos^®, Alltech Inc., USA) in the diet on the caecal volatile fatty acids (VFA) and pH of rabbits from 34 to 90 days of age. Three experimental diets were compared: control diet, zinc bacitracin (ZnBac) diet (control diet with 0.1 g ZnBac/kg feed) and MOS diet (control diet with 2.0 g MOS/kg feed). Rabbits were slaughtered at 34, 48, 69 and 90 days of age and caecal contents were collected and analyzed for dry matter, pH and VFA concentration. The empty caecum and caecal contents weights relative to live weight were also determined.Age affected (P<0.0001) VFA concentration and pH values in the caecum. The pH decreased with age whereas VFA concentration increased. Rabbits fed MOS had higher (P<0.05) VFA and tended (P=0.098) to had lower pH in the caecum than rabbits fed ZnBac and control diets. Acetic, propionic and butyric acids concentrations in the caecum increased with MOS but its molar proportions were similar among diets. Diet had no effect on empty caecum weight and caecal contents weight and dry matter concentration. There was no interaction effect between diet and age. From 34 to 90 days of age, VFA production was higher (P<0.05) in the caecum of rabbits fed MOS than in those fed ZnBac diet and control diet.The addition of MOS to the diet increased the VFA concentration in the caecum of growing rabbits from 34 to 90 days of age.     

Effects of graded dose dietary supplementation of Piper betle leaf meal and Persicaria odorata leaf meal on growth performance,apparent ileal digestibility,and gut morphology in broilers

Due to antimicrobial resistance and the public health hazard of antibiotic growth promoters, there is a grave need to find potential alternatives for sustainable poultry production. Piper betle (PB) and Persicaria odorata (PO) are herbs, which have been reported for antimicrobial, antioxidant, and anti-inflammatory properties. The present study aimed to estimate the influence of different dose supplementation of Piper betle leaf meal (PBLM) and Persicaria odorata leaf meal (POLM) on growth performance, ileal digestibility and gut morphology of broilers chickens. A total of 210 one day-old broiler chicks were randomly grouped into 7 treatments, and each treatment group has 3 replicates (n = 10) with a total number of 30 chicks. The treatments included T₁ control (basal diet (BD) with no supplementation), T₂ (BD + 2 g/kg PBLM); T₃ (BD + 4 g/kg PBLM), T₄ (BD + 8 g/kg PBLM), T₅ (BD + 2 g/kg POLM), T₆ (BD + 4 g/kg POLM), T₇ (BD + 8 g/kg POLM). Growth performance, gut morphology and ileal digestibility were measured. Except for T₄ (8 g/kg PBLM), graded dose inclusion of PBLM and POLM increased (P < 0.05) the body weight gain (BWG), positively modulated the gut architecture and enhanced nutrient digestibility in both stater and finisher growth phases of broiler chickens. Birds fed on PBLM 4 g/kg (T₃), and POLM 8 g/kg (T₇) had significantly higher (P < 0.05) BWG with superior (P < 0.05) feed efficiency in the overall growth period. Chickens fed on diets T₃ and T₇ had longer (P < 0.05) villi for duodenum as well as for jejunum. Furthermore, the birds fed on supplementations T₃ and T₇ showed improved (P < 0.05) digestibility of ether extract (EE), and dry matter (DM) compared to the control group. However, least (P < 0.05) crude protein (CP) digestibility was recorded for T_4. In conclusion, dietary supplementations of PBLM 4 g/kg and POLM 8 g/kg were positively modulated the intestinal microarchitecture with enhanced nutrient digestibility, resulted in maximum body weight gain, thus improved the growth performance of broiler chickens.     

The potential of Commelina benghalensis as a forage for ruminants

To evaluate the potential of Commelina benghalensis as a forage for ruminants, effects of plant maturity on chemical composition, rumen degradability as well as its increased dietary inclusion level on intake, digestibility and N balance in sheep fed Sorghum almum were investigated with forage obtained from the wild, re-established and harvested at 6, 10 and 14 weeks of growth. Composite herbage samples were analyzed for dry matter (DM), chemical components, total extractable phenolics (TEP) and amino acid content. In sacco rumen degradability measurements used six individually confined wethers (8 ± 0.5 months of age; 21 ± 2.6 kg live-weight (LW)) fitted with rumen cannulae and fed a ration of 3:1 fresh S. almum and Medicago sativa hay (about 1:2 on a DM basis). In sacco bags containing 5 g each of dry herbage were inserted into the rumen and withdrawn sequentially after 0, 12, 24, 36 and 48 h. Metabolizable energy (ME) was estimated from 24 h in vitro gas production. In the digestibility study, 12 wethers fitted with rumen canula were housed in metabolic crates and allotted to four treatment diets (i. e., D0, D10, D20 and D30) constituted from fresh S. almum and pre-wilted C. benghalensis in a randomized complete block design. The control diet (D0) was 3 kg fresh S. almum (≈535.5 g DM/wether/d about 30 g/kg LW), whereas D10, D20 and D30 were D0 +300, 600 or 900 g of wilted C. benghalensis (≈34, 68 or about 102 g DM/wether/d), respectively. The study lasted for 21 d. Dry matter, fibre and TEP content increased (P<0.001) with maturity of the forage, whereas those of CP and EE decreased (P<0.0001) over the same period. Amino acids (AA) also declined with maturity (P<0.05). Rumen degradability of DM and OM were unaffected, but DM intake increased linearly (P<0.0001) at a decreasing rate (Q: P<0.05) and DM digestibility (DMD) and N intake increased linearly (P<0.01 and P<0.0001, respectively) as level of C. benghalensis in the diet increased. Results indicate that advancing maturity affected chemical composition, but not rumen degradability, of C. benghalensis and also demonstrated that inclusion of C. benghalensis in S. almum diet improved intake, digestibility and N intake, suggesting its potential use as a feed supplement.     

Rumen degradable nitrogen requirements for optimum microbial protein synthesis and nutrient utilization in sheep fed on finger millet straw (Eleucine coracana) based diet

Studies were conducted to determine the rumen degradable nitrogen (RDN) requirement levels for optimum microbial protein synthesis and nutrient utilization in Nellore rams fed on finger millet straw (FMS) based diet. Thirty six Nellore sheep were randomly divided into four groups of nine animals each using the balanced completely randomized design. Animals in all the groups were fed finger millet straw as a basal roughage and groundnut cake (GNC) was offered daily in two equal halves in the morning (8.00 AM) and evening (4.00 PM) as RDN source. The animals in group I (GI) were fed with ad libitum FMS. Animals in group II, III and IV (GII, GIII, and IV) were offered GNC @ 12.4, 16.6, and 21.1 g RDN/kg digestible organic matter (DOM) along with FMS. The daily total dry matter (DM) and organic matter (OM) intakes linearly increased (P<0.05) with increasing level of RDN supplementation while there was no difference in total DM and OM intake/kg W^0.75 among different experimental groups. The digestibility coefficients of DM (P<0.001), OM (P<0.001), crude protein (CP) (P<0.001), ether extract (EE) (P<0.001), neutral detergent fibre (NDF) (P<0.01) and acid detergent fibre (ADF) (P<0.03) increased quadratically with increasing level of RDN supplementation from GI to GIV. The purine derivatives (PD) excretion, microbial purine absorption and microbial nitrogen supply (MNS g/day) linearly increased (P<0.001) as the level of RDN supplementation increased. There was no difference in nitrogen capture efficiency (NCE) and microbial nitrogen to total urinary nitrogen ratio (MN:UN) among the RDN supplemented groups. This study indicated that 12 g RDN/kg digestible organic matter intake (RDN g/kg DOMI) or 18 g RDN/kg OM apparently digested in the rumen (RDN g/kg DOMR) may be adequate for optimum microbial protein synthesis and digestibility of nutrients, there by improved plane of nutrition in sheep fed on finger millet straw based diet.     

The effect of replacing rice straw with dry wormwood (Artemisia sp.) on intake,digestibility, nitrogen balance and ruminal fermentation characteristics in sheep

This study examined the effect of substituting dry wormwood (Artemisia sp.) for rice straw in sheep diets on intake and apparent digestibility in vivo, nitrogen (N) balance and ruminal fermentation characteristics. Four Corriedale×Polwarth sheep (51.7 ± 1.3 kg) were individually housed in metabolism cages and fed diets (ad. libitum) with a 70:30 forage to concentrate ratio (DM basis), in which the basal rice straw was substituted with 0 (Control), 30 (LW), 50 (MW) or 100 (HW) g/kg of dry wormwood. The experimental design was a 4×4 latin square design in which 10 days of dietary adaptation was followed by 6 days of total feces and urine collection in each period. Rumen fluid was collected from a stomach tube at −0.5, 0.5, 1, 2, 4, and 8 h after the morning feed on day 6 of each collection period and analyzed for volatile fatty acids (VFA). The intakes of dry matter (DM), organic matter intake (OM), crude protein (CP), ether extract (EE), neutral detergent fibre (NDF) and acid detergent fibre (ADF) were higher (P<0.05) in sheep fed diets containing wormwood, than those fed the Control diet. Compared to the Control diet, CP digestibility was higher (P<0.05) in sheep fed MW and N intake, retained N, EE digestibility, urinary purine derivatives and microbial N yield were higher (P<0.05) in sheep fed diets, containing wormwood. Rumen pH was unaffected by treatment. Rumen NH₃-N and VFA concentrations were similar across treatments except that most values for diets containing wormwood were higher (P<0.05) than those for the control diet within the first 2 h of feeding. The non-glucogenic acid ratio was also similar across Control, LW and MW treatments, but it was generally lower in MW versus the Control treatment. In conclusion, substituting wormwood for rice straw in the sheep diets increased feed intake, rumen fermentation, in vivo digestibility, N retention and microbial N yield, particularly at the medium and high levels of wormwood inclusion.     

The interaction between lactose level and crude protein concentration on piglet post-weaning performance,nitrogen metabolism,selected faecal microbial populations and faecal volatile fatty acid concentrations

A performance study and a nitrogen balance study (2×3 factorial) were conducted to investigate the interaction between lactose level (215 and 125 g/kg) (lactofeed 70; 860 g whey permeate/kg, 140 g soya bean meal/kg, Volac International, UK) and crude protein (CP) concentration (160, 185 and 210 g/kg) on post-weaning piglet performance, nitrogen metabolism, faecal microbiology and faecal volatile fatty acid concentrations. In the performance trial, 252 piglets (7.6 kg; 33 days of age) were assigned to one of six dietary treatments following a 12-day period on a commercial creep diet (17 MJ/kg DE, 16 g lysine/kg). The experimental diets were fed for 28 days (days 12–40) and were formulated to have identical digestible energy (15 MJ/kg) and total lysine (14.5 g/kg) contents. In the N balance experiment, 24 boars (20 kg live weight) were offered the same diets as in the performance trial. Faecal samples were collected for selected microbial populations. There was an interaction (P<0.05) between lactose and CP concentration in daily gain (ADG) and daily feed intake (ADFI) (P<0.01) during the weaner period (days 12–40). At the high lactose level there was a linear increase in ADG and ADFI with increasing CP. However, at the low lactose level there was no increase in ADG or ADFI above the medium CP. Pigs offered 215 g lactose/kg had a higher dry matter (P<0.001), organic matter (P<0.001), energy (P<0.001), nitrogen (P<0.01) and neutral detergent fibre (P<0.05) coefficient of total tract apparent digestibility compared to pigs offered 125 g lactose/kg. There was an interaction between lactose and CP concentration for nitrogen intake (NI) (P<0.05), urine pH (P<0.05) and selected faecal microbial populations. At the high CP level, pigs offered diets containing 215 g lactose/kg had a higher NI and a lower urine pH than pigs offered 125 g lactose/kg (P<0.05). However, the inclusion of lactose had no significant effect on either NI or urine pH at the low or medium CP concentration. At the low lactose level there was a linear increase in faecal E. coli population and a linear decrease in faecal Lactobacilli population with increasing CP. However at high lactose levels CP concentration had no effect on either E. coli or Lactobacilli populations. Pigs offered 215 g lactose/kg had a significantly higher Bifidobacteria population compared to pigs offered 125 g lactose/kg. There was a linear decrease in Bifidobacteria population as CP increased. In conclusion, at the high lactose level there was a linear increase in ADG and ADFI with increasing CP concentrations. There was no increase in these parameters above 185 g CP/kg at the low lactose level.     

Effects of alfalfa silage storage structure and roasting corn on ruminal digestion and microbial CP synthesis in lactating dairy cows

The objective of this experiment was to quantify the effects of unroasted or roasted ground-shelled corn (GSC), when fed with alfalfa ensiled in bag, bunker, or O2-limiting tower silos on ruminal digestion and microbial CP synthesis in lactating dairy cows. The roasted corn was heat-treated in a propane-fired roasting system. Alfalfa was harvested as second cutting from fields with regrowth of the same maturity. A portion of each field was allotted to each silo. The diets with 3 × 2 factorial arrangement of treatments were fed to six multiparous rumen-cannulated Holstein cows in a cyclic change-over design with five 21-day periods. Experimental diets were comparable and averaged (on dry matter (DM) basis): 410 g/kg alfalfa silage (AS), 150 g/kg corn silage, 350 g/kg GSC, 50 g/kg soybean meal, 40 g/kg roasted soybeans, 177 g/kg CP, 264 g/kg NDF and 250 g/kg starch. Nutrient flow was quantified by the omasal sampling technique with use of three markers (Co, Yb and indigestible NDF). Continuous infusion of 10% atom excess (15NH4)2SO4 was used to label microbial CP. None of the interactions between storage structure of dietary AS and corn type were significant. DM intake was not different among dietary treatments, averaging 24.5 kg/day across diets. Means of ADF digested in the rumen for cows fed diets with AS from bag, bunker and O2-limiting tower silo were 2.1, 1.7 and 2.1 kg/day, respectively, and was lower in cows fed AS from the bunker silo. This response may partly be a reflection of the higher intake of ADF by cows fed AS ensiled in the O2-limiting tower silo compared with the bunker. There was a slightly greater supply of fermentable substrates for cows fed diets with roasted compared with unroasted GSC. The small increases in yield of milk protein and lactose observed in the previous production trial in cows fed diets containing roasted corn may have occurred because of greater supply of fermentable substrates.     

Effect of organic zinc supplementation on growth, nutrient utilization and mineral profile in lambs

To study the efficacy of organic zinc (Zn) supplementation on growth, nutrient utilization and mineral profile as compared to inorganic source [zinc sulphate (ZnSO₄)], 18 Muzaffarnagari male lambs of 11.30 ± 0.45 kg mean body weight (4–5 months of age) were divided into three groups of six animals in each in a randomized block design. Lambs in the control group were fed a standard total mixed ration (TMR) consisted of 60 kg/100 kg of concentrate mixture (CM) and 40 kg/100 kg of wheat straw. CM was consisted of 300 g/kg crushed maize grain, 270 g/kg soybean meal, 400 g/kg wheat bran, 20 g/kg mineral mixture (without Zn) and 10 g/kg common salt. Animals in the experimental groups were additionally supplemented with 20 mg Zn/kg of diet either through inorganic (ZnSO₄) or organic [Zn-methionine AA complex (Zn-meth)] sources. Experimental feeding was done for a period of 150 days including a 6 days metabolism trial. The intake of dry matter (DM), organic matter (OM), crude protein (CP), digestible CP and total digestible nutrients and digestibility of DM, OM, CP, ether extract, neutral detergent fibre and hemicellulose were comparable (P>0.05) among the three groups. However, digestibility of cellulose and acid detergent fibre was significantly (P<0.05) higher in Zn-meth group as compared to control group. Though the balance of calcium was adversely affected (P<0.01) in both the Zn supplemented groups, but it was significantly higher in Zn-meth group compared to ZnSO₄ group. While apparent absorption and retention of nitrogen, phosphorus, copper, iron and manganese were similar (P>0.05) among different groups, retention of Zn (P<0.05) as well as its concentration in the serum (P<0.01) were highest in Zn-meth group, followed by ZnSO₄ group and lowest in the control group, suggesting higher bioavailability of Zn from Zn-meth as compared to ZnSO₄. Average daily gain of the lambs and feed conversion efficiency were also significantly (P<0.05) higher in Zn-meth group as compared to control and ZnSO₄ groups, suggesting a positive role of organic zinc supplementation on the performance of lambs.     

Effects of dietary sodium butyrate supplementation on the intestinal morphological structure,absorptive function and gut flora in chickens

A study was carried out to investigate the effects of dietary sodium butyrate (SB) on the intestine and growth performance in chickens. Three hundred and thirty six day-old AA broiler chicks were allocated at random into four groups with six replicates each. Four groups were fed with basal diet (control) or diets supplemented with SB at the level of 500, 1000, 2000 mg/kg. Body weight gain increased linearly during the period from 0 to 21 days as the dietary supplementation of SB increased (P<0.05). Dietary supplementation of SB influenced feed conversion ratio (FCR) in a positive quadratic fashion during the period from 0 to 42 days (P<0.05). Dietary SB did not influence the absorptive function of jejunum (P>0.05). The concentrations of DNA, RNA, and protein in duodenal mucosa showed negative quadratic responses to the increase of dietary SB supplementation level (P<0.05). The ratio of villus height to crypt depth increased linearly with the increase of dietary SB supplementation (P<0.01). The Lactobacillus count decreased linearly with the increase of dietary SB supplementation (P<0.01).     

Dietary level of fibre and age at weaning affect the proliferation of Clostridium perfringens in the caecum, the incidence of Epizootic Rabbit Enteropathy and the performance of fattening rabbits

An experiment was conducted to investigate the effects of dietary fibre content and weaning age on Clostridium perfringens proliferation in the caecum and fattening mortality in growing rabbits farmed in a facility having Epizootic Rabbit Enteropathy. The experiment consisted in a 2 × 2 factorial arrangement with two weaning ages (28 days vs. 42 days) and two levels of dietary neutral detergent fibre assayed with a heat stable amylase and expressed exclusive of residual ash (aNDFom; 330 g/kg vs. 425 g/kg). Controls were made during two consecutive experimental periods that differed in hygienic environmental conditions by modifying the intensity of cleaning and disinfection in the farm previous to the trial. An interaction (P<0.001) was detected among the independent variables studied on Cl. perfringens enumeration in the caecal contents, as minimal values for this trait were obtained in non-medicated animals reared in a clean environment, and especially when they were weaned at a later age and fed the diet with the lower fibre content. The treatments studied also led to a variation in fattening mortality (from 4.7% to 34.0%), which was highly and positively correlated (P<0.001) to the average Cl. perfringens caecal counts in each combination of treatments. The results of the current study indicate that high counts of Cl. perfringens in the caecum can be used as an indicator of Epizootic Rabbit Enteropathy, and suggest that strategies designed to control its proliferation in the caecum might help to limit fattening mortality in rabbit fed diets not-medicated with antibiotics.     

Impact of diet composition on ileal digestibility and small intestinal morphology in early-weaned pigs fitted with a T-cannula

Piglets, separated from their dam at 12 days of age and fed a milk substitute hourly, were used as a model for suckling. Animals were fitted with a terminal ileal T-cannula and a jugular vein catheter. At 28 days of age, half of the pigs had a dietary change to a cereal-based weaner diet fed as slurry, and the others remained on milk substitute. Animals were labelled by oral administration of 15N-labelled yeast for 10 days (days 15 to 25). Blood samples were taken twice a day to monitor 15N enrichment of the blood plasma. Diets included polyethylenglycol (PEG 4000) to allow calculation of apparent ileal digestibility of nitrogen and individual amino acids. Ileal bacterial nitrogen was calculated from D-alanine content of the digesta. Furthermore, small intestinal (SI) villus height and crypt depth were measured. Feed intake was increased by the dietary change. The total nitrogen flow was 3.2 ± 0.4 g/day and 5.9 ± 0.4 for the milk and weaner diet, respectively. Endogenous nitrogen flow at the terminal ileum was similar for both groups (milk diet 2.4 ± 0.4 v. weaner diet 2.2 ± 0.3 g/day), whereas the bacterial nitrogen content (0.08 ± 0.01 g/day milk diet v. 0.15 ± 0.01 g/day weaner diet, P < 0.01) and exogenous nitrogen flow (0.94 ± 0.16 g/day milk diet v. 3.29 ± 0.12 g/day weaner diet, P < 0.001) increased significantly in the weaner-diet group. The ileal apparent digestibility coefficient of protein was 0.81 ± 0.06 and 0.68 ± 0.01 for the milk replacer and the weaner diet, respectively. Morphology measurements made along the SI at 25%, 50% and 75% were similar between piglets fed milk replacer and those fed a cereal-based weaner diet. The only statistical effect (P < 0.01) of dietary change was an increase in crypt depth in the weaner-diet group. In conclusion, pigs, following a dietary change analogous to weaning, lack the capacity to fully digest a standard weaner diet. This may result in an increased nutrient content entering the large intestine and an altered microbiota. In the absence of a period of anorexia, often associated with traditional weaning, we saw no evidence of villous atrophy, but report here a significant crypt hyperplasia, especially at the 75% level, as a result of dietary change.     

Chemical composition, in situ ruminal degradability and post-ruminal disappearance of dry matter and crude protein from the halophytic plants Kochia scoparia, Atriplex dimorphostegia, Suaeda arcuata and Gamanthus gamacarpus

Samples of Kochia (K. scoparia), Atriplex (A. dimorphostegia), Suaeda (S. arcuata) and Gamanthus (G. gamacarpus) were collected and analyzed for chemical composition including crude protein (CP), ether extract (EE), ash, neutral detergent fiber (NDFom), acid detergent fiber (ADFom), non-protein N (NPN), Ca, P, Na, K, Cl, Mg, Fe, Cu and Se. In addition, in situ ruminal degradability and post-ruminal disappearance of dry matter (DM) and CP of the samples using a mobile bag technique were determined. Results indicate that the chemical composition of Kochia and Atriplex was notably different from those of Suaeda and Gamanthus. All of these halophytic plants had high concentrations of Na, K, Cl, Cu and Se, and low levels of Ca, P and Mg. The rapidly degradable fractions of DM and CP (g/g) of Kochia (0.31 and 0.35, respectively) and Atriplex (0.39 and 0.50, respectively) were lower than for Suaeda (0.53 and 0.55, respectively) and Gamanthus (0.56 and 0.66, respectively). Ruminal DM and CP disappearance of Kochia (444 and 517 g/kg, respectively) and Atriplex (472 and 529 g/kg, respectively) were lower (P<0.05) than those of Suaeda (553 and 577 g/kg, respectively) and Gamanthus (663 and 677 g/kg, respectively) (P<0.05) using the mobile bag technique. Suaeda had the lowest (P<0.05) NDFom and ADFom disappearance (214 and 232 g/kg, respectively) in the rumen. Kochia scoparia and Atriplex dimorphostegia have more beneficial chemical nutritive components and digestible values versus Suaeda arcuata and Gamanthus gamacarpus.     

Effect of Ascophyllum nodosum extract on growth performance, digestibility, carcass characteristics and selected intestinal microflora populations of grower–finisher pigs

The effects of an extract of the brown seaweed Ascophyllum nodosum (AN) in grower–finisher pigs are reported. In Experiment 1, the effect of dietary supplementation with increasing levels of AN extract (ANE) on growth performance, carcass characteristics and gastrointestinal microflora was investigated. A total of 360 pigs were randomly allocated, based on initial live-weight and sex, to one of four experimental treatments as follows; control diet (no ANE), control diet plus 3 g ANE/kg, control diet plus 6 g ANE/kg and control diet plus 9 g ANE/kg. These diets were fed ad libitum up to slaughter. In Experiment 2, eight male pigs were allocated to a control diet (no ANE) or the control diet plus 2.5 g ANE/kg to determine effects of ANE on coefficient of total tract apparent digestibility (CTTAD) of nutrients and nitrogen (N) balance. Supplementation with increasing levels of ANE in Experiment 1 resulted in reduced daily gain, carcass weight and kill-out yield during the combined grower–finisher period (P<0.05); however, there were no effects of treatment on feed intake, feed conversion ratio or carcass characteristics. Increasing levels of dietary ANE resulted in decreased ileal coliform counts (P<0.05). Increasing dietary ANE also tended to increase adherent lactobacilli in the colon (P=0.080) but caecal bifidobacteria declined (P<0.05). There were trends towards a linear reduction in colonic bifidobacteria (P=0.077) and towards a quadratic effect on rectal lactobacilli (P=0.077). Intestinal pH was unaffected by ANE supplementation (P>0.05). In Experiment 2, the CTTAD was unaffected by the inclusion of ANE (P>0.05). Overall, the intestinal coliform reductions obtained suggest that ANE may provide a dietary means to improve gut health and potentially reduce pathogen carriage in finishing pigs. However, the negative effects on growth performance observed in healthy animals will most likely limit the commercial use of dietary ANE as a feed additive.