B.P. Mullan

A review of the potential of Lathyrus sativus L. and L. cicera L. grain for use as animal feed

The use of two closely related species, Lathyrus cicera and L. sativus, as grain legumes for human and animal consumption, dates to the Neolithic period. Due to its tolerance to harsh environmental conditions L. sativus is still used widely for human food in Ethiopia and the Indian sub-continent, although cultivation has diminished in many other regions. The grain of both L. cicera and L. sativus contains a neurotoxin, 3-(-N-oxalyl)-L-2,3-diamino propionic acid (ODAP), which can cause a paralysis of the lower limbs (lathyrism). Due to the occurrence of lathyrism in humans recent plant breeding has produced cultivars with low ODAP concentrations. The susceptibility of animal species to lathyrism is poorly understood, although horses and young animals are more susceptible. Older published animal feeding studies are of limited use, since the presence and role of ODAP was unknown until the 1960s. More recent feeding studies indicate that low ODAP lines of L. cicera or L. sativus can be safely incorporated at inclusion rates up to 40, 30 and 70% of the diet of poultry, pigs and sheep, respectively, without growth reductions. The compositions of both L. cicera and L. sativus are similar to other commonly used feed grain legumes, respective protein contents are 25 and 27%. Antinutritional factors (ANFs), other than ODAP, are present in both L. cicera and L. sativus at concentrations similar to those found in other grain legumes; including trypsin inhibitors, chymotrypsin inhibitors, amylase inhibitors, lectins, tannins, phytate and oligosaccharides. The effect of ANFs in L. cicera and L. sativus on animal performance is not well understood and sometimes confounded with ODAP effects. Heating of grain will reduce levels of the proteinaceous ANFs and in some cases ODAP as well. Variation recorded in the germplasm of L. cicera and L. sativus has not been greatly utilised in plant breeding to lower levels of ANFs, with the exception of ODAP, leaving considerable potential for rapid improvement of cultivars. L. cicera and L. sativus are low production cost legumes

Increasing viscosity of the intestinal contents alters small intestinal structure and intestinal growth, and stimulates proliferation of enterotoxigenic Escherichia coli in newly-weaned pigs

Sources of viscous soluble fibre, such as barley and oats, have often been included in the weaning diet of the pig to accelerate development of the large intestine. Inclusion of a non-fermentable, viscous compound, sodium carboxymethylcellulose (CMC), in a low-fibre weaning diet was tested to assess the influence of digesta viscosity on the gut in the absence of increased fermentation. Two CMC sources, of low and high viscosity, were added to cooked rice-based diet at 40 g/kg total diet. A third control rice diet did not contain any CMC. Diets were fed for 13 d following weaning at 3 weeks of age. Addition of CMC to the diet significantly increased the intestinal viscosity of digesta within the small (P<0.001) and large (P<0.05) intestine. No simple association was found between increases in intestinal viscosity and effects on intestinal morphology and whole-body growth. The average empty-body-weight gain and the small intestinal villus height increased with low-viscosity CMC, but decreased with the high-viscosity CMC group. The full large intestinal weight increased in all pigs fed CMC. Dietary CMC (both low- and high-viscosity) increased the percentage moisture of digesta and faeces, and was associated with increased faecal shedding of enterotoxigenic haemolytic Escherichia coli. Feed ingredients in weaning diets that excessively increase the viscosity of the intestinal digesta may be detrimental to pig health and production.

A chemical analysis of samples of crude glycerol from the production of biodiesel in Australia, and the effects of feeding crude glycerol to growing-finishing pigs on performance, plasma metabolites and meat quality at slaughter

Theaimsofthisstudywereto:(i)determinethechemicalcompositionof11samplesofcrudeglycerolcollected from seven Australian biodiesel manufacturers; and (ii) examine the effects of increasing levels of crude glycerol fed to growing-finishing pigs on performance, plasma metabolites and meat quality at slaughter. Chemical composition of crude glycerol samples varied considerably; glycerol content ranged between 38 and 96%, with some samples containing up to 29% ash and 14% methanol. One of these samples (76.1% glycerol, 1.83% methanol) was then fed to 64 female pigs (50.95.55kg;means.d.)allocatedtooneof fivedietarytreatments(0,4,8,12and16%crudeglycerol)untiltheyreached 105 kg liveweight. There were no statistical differences in performance indices with increasing levels of added glycerol, althoughtherewasanunexpectedlyhighvariationbetweentreatments.Bloodglycerollevelswereunaffectedbydietinweek two of the experiment, but increased linearly (P 0.05).Dietscontainingaddedcrude glycerolwerelessdustyaftermixing,butdietsthatcontained8,12and16%glycerolallformeda firmaggregatewithin24hof mixing that presented some feeding difficulties. This might restrict inclusion of glycerol in mash diets to dietary levels less than8%.Furthermore,levelsofresiduessuchasmethanolandashshouldbemonitoredtopreventexcessiveamountsofthese compounds in pig diets.

Feeding a diet with decreased protein content reduces indices of protein fermentation and the incidence of postweaning diarrhea in weaned pigs challenged with an enterotoxigenic strain of Escherichia coli

This study evaluated the effect of feeding low protein (LP) diets for 7 or 14 d after weaning or a high protein (HP) diet for 14 d after weaning on postweaning diarrhea (PWD), indices of protein fermentation, and production in pigs infected or not infected per os with an enterotoxigenic strain of Escherichia coli. A total of 72 female pigs weaned at aged 21 d with initial BW of 5.9 +/- 0.12 kg were used in a 3 x 2 factorial arrangement of treatments. The factors were 3 feeding regimens associated with different combinations of feeding duration and diet CP level: (i) HP diet (256 g of CP/kg) fed for 14 d after weaning, (ii) LP diet (175 g of CP/kg) fed for 7 d after weaning, and (iii) LP diet fed for 14 d after weaning; and infection or noninfection with an enterotoxigenic strain of E. coli (10(7) cfu/mL, serotype O149:K91:K88) at 72, 96, and 120 h after weaning. The LP diets were fortified with crystalline Ile and Val to achieve an ideal AA pattern. A second-stage diet (213 g of CP/kg) was fed to pigs at the conclusion of each feeding regimen, and the study finished 4 wk after weaning. None of the diets contained antimicrobials. Feeding the LP diets decreased (P < 0.001) plasma urea nitrogen, fecal ammonia nitrogen concentrations, and the incidence of PWD, but increased (P = 0.001) fecal DM content compared with pigs fed HP in the 2-wk period after weaning. Infection increased shedding of beta-hemolytic E. coli (P < 0.001), the incidence of PWD (P < 0.001), and fecal ammonia nitrogen concentrations (P < 0.01), but did not interact with feeding regimen, after weaning. Pigs challenged with E. coli grew more slowly (P < 0.001) and had decreased G:F (P < 0.01) compared with nonchallenged pigs in the 4-wk period after weaning. Feeding an LP diet for 7 or 14 d after weaning markedly reduced the incidence of PWD after infection with beta-hemolytic E. coli. Infection was associated with decreased indices of protein fermentation in the distal gastrointestinal tract but did not compromise the growth of weaner pigs in the 4-wk period after weaning.

The influence of piglet body weight on milk production of sows

Abstract Thirty sows were allocated at their first farrowing to three experimental treatments: Control foster (CF), sows which suckled piglets which were between birth and 29 days of age; newborn foster (NBF), sows which suckled piglets between birth and 17 days of age followed by piglets between 2 and 28 days old; or two-week foster (TWF), sows which suckled piglets between 17 and 29 days of age. Within each experimental block, CF and NBF sows farrowed on the same day and the TWF sows farrowed 15.0 ± 0.3 days later. Litter size was standardized to 9 pigs by fostering within one day of farrowing. Litters were exchanged between each of the three cross foster treatments 1.7 ± 0.3 days after TWF sows farrowed; litters suckling NBF sows were transferred to CF sows, litters suckling CF sows were transferred to TWF sows and the relatively newborn litters suckling TWF sows were transferred to NBF sows. This experimental design enabled the separation of the effect of body weight of the piglet from the effect of stage of lactation of the sow, on sow milk production. Pigs were weaned at about four weeks of age which resulted in lactation lengths for CF, NBF and TWF sows being 28.9 ± 0.4, 42.5 ± 0.8 and 15.0 ± 0.4 days, respectively. TWF sows produced more milk between d 4–8 of lactation than NBF or CF sows (9.13 versus 7.61 and 6.85 kg/d, respectively) but between d 11–15 of lactation, milk yield was not significantly different. After cross-fostering, the milk yield of NBF sows was less than that of CF sows between d 18–22 of lactation (6.65 versus 8.49 kg/d). But, again, between d 25–29 of lactation there was no significant difference in milk yield between NBF and CF sows. The cross-foster treatments had no significant effect on the composition of milk collected from sows throughout lactation. The positive relationship between piglet body weight and milk consumption indicates that older, heavier piglets are able to remove more milk from the mammary glands of lactating sows.

Effects of feeding low protein diets to piglets on plasma urea nitrogen, faecal ammonia nitrogen, the incidence of diarrhoea and performance after weaning

This study evaluated the effects of feeding pigs low protein (LP) diets for different lengths of time after weaning on indices of protein fermentation, the incidence of post-weaning diarrhoea (PWD), growth performance, and total-tract apparent digestibility. Sixty weaner pigs weighing 6.1 ± 0.13 kg (mean ± SEM) were used in a completely randomised design having five treatments: (i) a high protein diet (HP, 243 g/kg CP) fed for 14 d after weaning (HP14); (ii) a low protein diet (LP, 173 g CP/kg) fed for 5 d after weaning (LP5); (iii) LP diet fed for 7 d after weaning (LP7); (iv) LP diet fed for 10 d after weaning (LP10), and (v) LP diet fed for 14 d after weaning (LP14). All diets were supplemented with lysine, methionine, tryptophan and threonine, with all LP diets additionally fortified with crystalline isoleucine and valine to conform to a proposed ideal amino acid (AA) pattern. A second-stage diet (215 g CP/kg) was fed to pigs at the conclusion of each treatment. None of the diets contained antimicrobial compounds. Feeding a LP diet, regardless of duration of feeding, decreased plasma urea nitrogen (p < 0.001) and faecal ammonia-nitrogen (p < 0.001) contents. Feeding a LP diet, irrespective of feeding duration, decreased the incidence of PWD at day 8 after weaning (p = 0.044), and pigs fed diets LP7, LP10 and LP14 had firmer faeces (p = 0.030, p = 0.047 and p = 0.007, respectively) between days 10 and 12 after weaning. Treatments LP5, LP7, LP10 and LP14 did not reduce (p > 0.05) growth performance up to 106 days after weaning compared to pigs fed the HP diet. Total-tract apparent digestibility of dry matter, energy and crude protein were similar (p > 0.05) between treatments. Our data suggest that feeding a LP diet, supplemented with AA to conform to an ideal AA pattern, for 7–10 days after weaning can reduce PWD in pigs fed antibiotic-free diets without compromising production.

Variation in the chemical composition of wheats grown in Western Australia as influenced by variety, growing region, season, and post-harvest storage

Two experiments were conducted to examine varietal and environmental influences on physical characteristics and chemical content in a cohort of wheats grown in Western Australia. In Expt 1, a 3 × 3 × 2 factorial experiment examined the relationships between wheat variety (Arrino, Stiletto, and Westonia), growing region (high, medium, and low rainfall zone), and 2 harvest years (1999 and 2000). In Expt 2, the effect of storage for 6 months on the chemical composition of the wheats was examined. Wide variations in the content of crude protein (CP, CV 19.4%), total starch (CV 5.45%), total non-starch polysaccharides (NSP, CV 9.4%), insoluble NSP (CV 10.4%), and soluble NSP (CV 20.7%) were observed. The crude protein content of wheat was inversely related to total starch content (r = -0.779, P < 0.001). Variety influenced fast digestible starch (P < 0.001), acid detergent fibre (ADF, P < 0.01), total NSP (P < 0.05), insoluble NSP (P < 0.05), and in vitro extract viscosity (P < 0.05). The annual precipitation level (mm) irrespective of growing region was correlated to bushel weight (r = -0.683, P < 0.01), CP (r = -0.631, P < 0.01), total starch (r = 0.526, P < 0.05), ADF (r = -0.687, P < 0.01), lignin (r = -0.863, P < 0.001), soluble NSP (r = 0.826, P < 0.001), and free sugar contents (r = -0.795, P < 0.001), indicating the importance of annual rainfall for accumulation of protein, carbohydrates, and lignin in wheats. Harvest year had a strong influence on chemical composition (P < 0.05 to <0.001) and bushel weight (P < 0.001) of wheat. Storage for 6 months decreased soluble NSP (P < 0.01), ADF (P < 0.05), and lignin content (P < 0.01), and increased free sugar content (P < 0.001). AR Chepose J. K et al

Effects of different sources and levels of dietary fibre in diets on performance, digesta characteristics and antibiotic treatment of pigs after weaning

An experiment was conducted in male weaner pigs to examine the effects of different sources and levels of dietary fibre (DF) on performance and aspects of fermentation and digestion after weaning. Pigs were allocated in a completely randomised design having five experimental treatments, with six pigs allocated to each treatment. The diets used were: (i) cooked white rice (R) plus an animal protein supplement (R-AP); (ii) R+HiMaize (high-amylose maize starch) (R-HACS); (iii) R+lupin isolate (R-LI); (iv) R+HiMaize+lupin isolate (R-HACS+LI); and (v) a commercially-based weaner diet (CAM). These ingredients were chosen because they represented a mix of soluble and insoluble sources of DF. The measured total DF content ranged from 27 g/kg in diet R-AP to 300 g/kg in diet R-LI. Pigs were fed on an ad libitum basis for 14 days, then euthanased for sample collection. Pigs fed diet R-AP consumed more dry matter (DM) (P = 0.037) than pigs fed diets R-HACS+LI and COM, and tended (P < 0.15) to show greater rates of live- and empty-bodyweight gain than pigs fed diets containing higher levels of DF. Fermentation indices such as pH and volatile fatty acid (VFA) concentrations were generally reduced (P < 0.05) in pigs fed diets R-AP and COM, particularly in the distal colon. The pool of VFA in the colon was greatest in pigs fed diets R-HACS, R-LI and COM (45, 45 and 36 mmol per pig, respectively, P < 0.001), and the colonic VFA pool explained proportionally 0.79 (P = 0.028) of the variation in the empty weight of the colon. The total intake of insoluble DF explained proportionally 0.75 and 0.80 of the variation in the quantity of colonic contents (P = 0.057) and the empty colonic weight (P = 0.041), respectively. In a retrospective analysis of the number of pigs treated with antibiotics for post-weaning diarrhoea, pigs offered diet R-AP did not require any treatment whereas pigs on all other diets required more injections (0 versus a median score of 3.0-4.5 injections, P = 0.004). Under the conditions of this experiment, pigs offered a diet based on cooked white rice, animal protein sources and 50 g/kg soyabean meal ate more feed after weaning and required no therapeutic antibiotic treatments compared to pigs offered higher levels of dietary DF. The possible implications of such findings are discussed.

Age, sex, and weight at weaning influence organ weight and gastrointestinal development of weanling pigs

The present study was designed to determine the interrelationships between sex, weaning age, and weaning weight on aspects of physiological and gastrointestinal development in pigs. Forty-eight Large White x Landrace pigs were used in a factorial arrangement with the respective factors being: age at weaning ( 14 or 28 days), weight at weaning ( heavy or light), sex ( boar or gilt), and time after weaning ( 1, 7, and 14 days). At weaning, 48 pigs were removed from the sow; 16 pigs were then fasted for 24 h before euthanasia for determination of organ weights, gut histology, and enzymology, and 32 pigs were offered a high quality pelleted weaner diet ad libitum for subsequent assessment of organ weights, histology, and enzymology at 7 and 14 days after weaning. On Day 6 and 13 after weaning, 2 pigs from each group had their feed removed, and 24 h later were euthanased and similar measurements were taken. In general, the data highlighted the overall gastrointestinal underdevelopment of pigs weaned at 2 weeks of age and of pigs weaned light-for-age at either 2 or 4 weeks. Heavier body organs, gastrointestinal organs, and accessory digestive organs observed after weaning, except for the spleen, presumably reflected the increase in substrates available for cellular growth as feed intake increased after weaning, and the development of organs required to process this feed. Interestingly, the relative weights (% of liveweight) of the stomach and small intestine and, to a lesser extent, the caecum and colon, were greater in the light, 14-day-old weaned pigs, but these differences diminished with increasing time after weaning. Consistent effects due to age, weight, and sex were not observed for villous height and crypt depth, or for the specific activities of the brush-border and pancreatic enzymes measured. However, increases (P < 0.001) in the activities of maltase (P < 0.001), glucoamylase ( P < 0.001), and sucrase (P = 0.020) ( all expressed per gram of mucosa), and that of trypsin ( per gram of pancreas), occurred by 14 days after weaning. This most likely reflected the inducible nature of these enzymes in response to the increasing intake of substrates provided in the diet. In contrast, the specific activity of lactase declined (P = 0.012) in the first 14 days after weaning. These data suggest that pigs weaned at 2 weeks of age and pigs weaned light-for-age at either 2 or 4 weeks have a less developed gastrointestinal tract, and that its development after weaning might proceed differently to that of pigs weaned older and heavier. (Less)

Addition of oat hulls to an extruded rice-based diet for weaner pigs ameliorates the incidence of diarrhoea and reduces indices of protein fermentation in the gastrointestinal tract

An experiment was conducted to determine whether adding oat hulls to weaner pig diets based on extruded rice or unprocessed wheat influenced post-weaning diarrhoea (PWD) and protein fermentation in the large intestine. Ninety-six male piglets (5.16 (SEM 0.08) kg) were allocated to (i) extruded rice plus animal proteins (RAP); (ii) RAP with added oat hulls (20 g/kg); (iii) wheat plus animal proteins (WAP); (iv) WAP with added oat hulls (20 g/kg). Blood and faecal samples were collected on days 7 and 14 after weaning at about age 21 d. Pigs fed RAP had more PWD than pigs fed WAP (P < 0.05). Oat hull supplementation to diet RAP decreased the incidence of PWD (P < 0.05). The total-tract digestibility of DM, starch and energy was higher in rice-based diets than in wheat-based diets (P < 0.001); however, oat hulls decreased digestibility of DM and gross energy (P < 0.001). Pigs fed RAP had higher plasma creatinine concentrations (P < 0.01), which were positively correlated to cumulative beta-haemolytic Escherichia coli scores after weaning (R2 0.928; P = 0.015). Addition of oat hulls decreased plasma urea concentrations only in pigs fed RAP (interaction; P < 0.05). Pigs fed RAP had lower faecal total biogenic amine concentrations than pigs fed WAP (P < 0.001). Oat hull supplementation tended to decrease total biogenic amine concentrations (P = 0.103). These data indirectly suggest that a mostly insoluble dietary fibre source such as oat hulls can decrease PWD in dietary situations where there may be a misbalance of carbohydrate to protein entering the hindgut.