R. H. King

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.

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.

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)

Lifetime and post-weaning determinants of performance indices of pigs

The present study was designed to determine the interrelationships between sex, weaning age, and weaning weight on subsequent growth performance. Ninety-six Large White × Landrace pigs were used in a 2 × 2 × 2 factorial experiment with the respective factors being: age at weaning (14 or 28 days), weight at weaning (heavy or light), and sex (boar or gilt). Eighty pigs were offered a high quality pelleted weaner diet ad libitum while the remaining 16 pigs (2 pigs from each treatment group) were removed from the sow and fasted for 24 h before being euthanased for determination of gut histology and enzymology. The remaining pigs were weaned into individual pens and given an ad libitum diet containing 15.5 MJ DE/kg and 0.95 g available lysine/MJ DE. On Day 6 and 13 after weaning, 2 pigs from each group at each time had their feed removed and, 24 h later, were euthanased. From 3 weeks post-weaning, the remaining pigs were group-penned with contemporary pigs and fed commercial rations until slaughter at 23 weeks of age. In the first week after weaning, the heavy pigs and those weaned at 28 days ate more feed and grew faster, and gilts ate more and grew faster than boars over the same time. Pigs that were heavier at weaning were also heavier at every subsequent age. At slaughter, heavy boars weighed more than heavy gilts (110.5 v. 103.7 kg, P = 0.027), whereas this was not the case for light boars and gilts (94.1 v. 94.4 kg, P = 0.96). Whereas there were no effects of sex or weight at weaning on P2 backfat depth, pigs weaned at 14 days had more backfat at 23 weeks than pigs weaned at 28 days (13.1 v. 10.9 mm, P = 0.009). In conclusion, these data clearly indicate that the greatest determinants of immediate post-weaning performance under the present conditions were the age and weight of the pigs at weaning. However, the key determinant of lifetime growth rate appeared to be weight of pigs at weaning or, by inference, birth. Although age at weaning had no effect on lifetime growth rate, early-weaned pigs were fatter at slaughter.

Responses to homeostatic signals in ractopamine-treated pigs

The beta-agonist ractopamine (RAC) promotes protein deposition with little effect on fat deposition in the pig. To assess whether the lack of effect on fat deposition was due to changes in response to homeostatic signals, eight crossbred gilts (73 kg body weight (BW)) with venous catheters were used to examine plasma metabolite and hormone concentrations before and after intravenous injections of insulin and the beta 2-agonist fenoterol during dietary RAC (0 or 20 mg/kg) treatment. Pigs received intravenous challenges of insulin (1 microgram/kg BW) on days 3, 9 and 23 and fenoterol (2 micrograms/kg BW) on days 4, 10 and 24 of treatment. RAC was then withdrawn from the diet and insulin and fenoterol challenges were repeated 6 and 7 d later respectively. Blood samples for the determination of metabolite and hormone concentrations were taken at -30, -20, -10, -1, 2.5, 5, 10, 20, 30, 45, 60 and 120 min relative to the challenges. Dietary RAC decreased basal plasma insulin concentrations but had no effect on plasma glucose or non-esterified fatty acids (NEFA). Hypoglycaemic responses to insulin were not affected by RAC while the anti-lipolytic effects of insulin tended to be augmented. Dietary RAC decreased the lipolytic response to fenoterol, this being evident after 4 d treatment. Hypoglycaemic response to fenoterol was not changed whereas the hyperinsulinaemic response to fenoterol was attenuated by dietary RAC. Previous treatment with RAC did not influence basal hormone and metabolite concentrations or responses to homeostatic signals during the withdrawal period. While these results suggest little change in glucose metabolism, the de-sensitization of adipose tissue beta-adrenergic receptors is consistent with the observations that dietary RAC has little effect on the rate of fat deposition in the growing pig.

Evaluation of solvent-extracted canola meal for growing pigs and lactating sows

The response of weaner pigs, grower/finisher pigs, and lactating sows to inclusion levels of solvent- extracted canola meal up to 250, 300, and 202 g/kg, respectively, was examined in 3 experiments. The average composition of the canola meal used in the experiments was 884 g DM/kg, 376 g CP/kg, 41 g fat/kg, 21.6 g lysine/ kg, 12.4 MJ digestible energy (DE)/kg, and 4.5 µmol glucosinolates/g. In all experiments, canola meal replaced other common protein sources in equal DE and equal lysine diets that were offered ad libitum to pigs. In Expt 1, 49 male pigs were weaned at 19.6 days of age and 6.27 kg liveweight and allocated to 7 diets containing 0-250 g/kg of canola meal for 42 days. Growth rate and voluntary feed intake were not significantly affected by level of canola meal up to 250 g/kg. However, there was a significant linear response in feed conversion ratio (FCR), indicating that as the level of canola meal increased, feed efficiency was improved. In Expt 2, pigs were randomly allocated at about 63 days of age and 24 kg liveweight to 16 group pens, each containing 12 pigs. Four pens were each allocated to one of 4 diets containing 0-300 g/kg canola meal up to slaughter at 140 days of age when pigs were approximately 97 kg liveweight. Canola meal level had no significant effect on growth performance, carcass quality, or weight of the thyroid gland. In Expt 3, 386 mixed parity sows were randomly allocated over a 70-day period to diets containing 0, 101, and 202 g/kg of canola meal that were offered during the lactation period of about 25 days. Average piglet growth between Day 3 and weaning was 244 g/day and was unaffected by inclusion level of canola meal in the sow diet. However, there was a significant positive linear response between sow feed intake and canola meal, which was particularly evident in the sows allocated during the initial period of the experiment when environmental temperatures were hotter. Average feed intake during lactation was 5.08, 5.50, and 5.67 for sows offered 0, 101, and 202 g/kg of canola meal, respectively. In conclusion, solvent-extracted canola meal can be included at levels up to 250, 300, and 202 g/kg in weaner pig, grower/finisher pig, and lactating sow diets, respectively, without adversely affecting the performance of these classes of pigs. A P. K andF u R f

The energy value of Lupinus angustifolius and Lupinus albus for growing pigs

Ninety male crossbred pigs were allocated at 30 kg live weight to a 6 5 factorial experiment involving six diets and five levels of feeding where average daily intakes were 1.11, 1.36, 1.67, 1.90 kg and ad libitum between 30 and 60 kg live weight. The control diet contained predominantly animal protein sources, another four diets contained 350 g/kg of either kernels or seeds of either L. angustifolius cv. Gungurru or L. albus cv. Kiev while the remaining diet contained 350 g/kg of peas. All diets were formulated to contain 15.3 MJ DE/kg and 0.7 g available lysine/MJ DE to ensure that dietary protein was adequate. Six estimates of the digestibility of each protein source were determined by the total faecal collection method. The digestible energy contents (SE) of L. angustifolius seed and kernel, L. albus seed and kernel and peas were 15.81 (0.18), 16.85 (0.76), 16.84 (0.34), 17.70 (0.47) and 14.98 (0.15) MJ/kg air dry, respectively. All pigs were killed at 60 kg live weight and the dressing percentage of pigs given L. angustifolius and L. albus diets were 2.6 and 4.7 units lower than the mean dressing percentage of pigs given the other diets. The major factors contributing to this reduction in dressing percentage when lupins were offered to pigs were gut fill and differences in intestinal weight. The relative energy value of the protein sources was assessed by comparing the relationship between the rates of energy deposition in the empty body and DE intake for the diets. The response of energy deposition to energy intake was similar for kernel and seed for both L. angustifolius and L. albus and thus data for kernel and seed were consolidated for both types of lupins. The respective linear relationships between energy deposited in the empty body (E, MJ/day)

Dietary lupins (Lupinus angustifolius and Lupinus albus) can increase digesta retention in the gastrointestinal tract of pigs

Lupins are high in crude protein, cell wall materials, and gross energy but uncertainty about the bioavailability of nutrients and adverse effects on feed intake limit their use in the pig industry. Three experiments were conducted to determine the effect of lupins on retention time in the digestive tract by determining the average time it took for ingested polyethylene beads to pass through the digestive tract of pigs fed wheat-based diets containing various lupin species and fractions. In Expt 1, pigs were restrictively fed (1.8 kg/day) diets containing either predominantly wheat or predominantly wheat plus 400 g/kg peas or L. angustifolius seeds or kernels. The retention times of diets containing 400 g/kg of L. angustifolius seeds or kernels were significantly greater than those containing wheat alone (66.4 and 64.3 v. 48.8 h, P > 0.05, s.e.d. = 7.7 h), while that for the diet containing 400 g/ kg peas was intermediate (55.8 h). In Expt 2 and 3, pigs were fed 1 of 6 wheat-based diets balanced for digestible energy (DE) and amino acid composition and containing either animal protein or 350 g/kg of peas, and L. angustifolius seeds or kernels, or L. albus seeds and kernels. Pigs were restrictively fed (1.5 kg/day) for Expt 2 or fed ad libitum for Expt 3. The mean retention time of the L. albus diets was greater than the other diets in both experiments. Feed intake and daily gain were reduced in pigs fed diets containing L. albus. Despite having lower feed intakes, pigs fed diets containing L. albus had more digesta in the stomach and small intestine at slaughter than the pigs consuming the diets not containing lupins. Appropriate physical treatment or enzymatic supplementation of L. albus diets may alleviate some of the feed intake problems.

The influence of dietary energy intake on growth performance and tissue deposition in pigs between 80 and 120 kg liveweight

Eighty crossbred pigs of a composite genotype were allocated at 80 kg liveweight to a 2 × 5 factorial experiment involving 2 sexes (boars and gilts) and 5 levels of dietary energy intake ranging from about 55% estimated ad libitum up to 100% ad libitum intake. The diet was formulated to be protein-adequate and contained 14.4 MJ DE/kg and 0.55 g available lysine/MJ DE and the pigs were slaughtered at approximately 120 kg liveweight. Growth rate and food conversion efficiency increased linearly, in response to increasing digestible energy (DE) intake, with boars consistently out-performing gilts at each level of DE intake. Protein deposition rate in the whole empty body of pigs was consistently higher in boars than in gilts and linearly related to DE intake in both sexes, with no evidence of a plateau at high energy intakes, suggesting no intrinsic limit to protein deposition in these pigs up to 120 kg liveweight. When pigs were offered the protein-adequate diet ad libitum between 80 and 120 kg liveweight, boars and gilts consumed 47.7 and 40.9 MJ DE/day, respectively, and protein deposition rates in the whole empty body of pigs reached 247 and 182 g/day, respectively. Maintenance energy requirements were estimated to be 351 kJ DE/kg 0.75 .day for both boars and gilts (maximal model; including nominal DE level (treated as a 5-level factor), actual DE intake (treated as a continuous variable), and sex (treated as a 2-level factor)) or 506 and 566 kJ DE/kg 0.75 .day for boars and gilts, respectively (reduced model; including actual DE intake (treated as a continuous variable) and sex (treated as a 2-level factor)). Statistical analyses show that the maximal model reflects the data more closely than the minimal model, suggesting that the lower maintenance estimate of 351 kJ DE/kg 0.75 .day could reflect reality better. In conclusion, genetically improved boars, and to a lesser extent gilts, have a high capacity for lean growth, and their upper limit to protein retention might not be reached below about 120 kg liveweight.

Interactions between weaning age, weaning weight, sex, and enzyme supplementation on growth performance of pigs

Digestive capacity of early-weaned pigs may be insufficient to fully digest many ingredients currently used in weaner diets. Ihe aim of this experiment was to determine whether an exogenous enzyme preparation with broad carbohydrase activity could benefit pigs that developmentally might be immature at weaning, especially with regard to gastrointestinal development. Eighty Large White x Landrace pigs were used in a 2 × 2 × 2 × 2 factorial experiment with the factors being: weaning age (14 or 24 days), weaning weight (heavy or light), sex (boar or gilt), and dietary Biofeed Plus CT (0 or 500 μg/g), which contained fungal xylanases, pentosanases, and β-glucanases. Pigs were housed individually and given a wheat-based (550 g/kg) diet containing 15.0 MJ DE and 15.9 g lysine/kg on an ad libitum basis for 21 days. The diet also contained 50 g/kg of soybean meal and 50 g/kg of lupin (Lupinus angustifolius) kernels. The liveweights of heavy (H) pigs weaned at 24 or 14 days and light pigs (L) weaned at 24 or 14 days were 7.9 and 5.3 and 5.2 and 3.9 kg, respectively. Pigs weaned at 14 days grew slower (157 v. 345 g/day) than those weaned at 24 days, although there was a suggestion of an interaction between age and weight at weaning (P = 0.081). Thus, H and L pigs weaned at 14 days grew at 148 and 166 g/day, whereas H and L pigs weaned at 24 days grew at 374 and 315 g/day, respectively. Although there was no main effect of enzymes on daily gain (248 v. 254 g/day, P = 0.80), feed intake (278 v. 284 g/day, P = 0.79), or feed conversion ratio (1.19 v. 1.25, P = 0.35), there were interactions with weaning age on daily gain (P = 0.050) and feed intake (P = 0.060). Pigs weaned at 14 days grew slower (176 v. 138 g/day) and ate less (206 v. 174 g/day), whereas pigs weaned at 24 days grew faster (321 v. 369 g/day) and ate more (351 v. 394 g/day), when supplemented with enzymes. During the third week after weaning there were interactions between dietary enzymes and sex (P = 0.060) and dietary enzymes and age (P = 0.023) on daily gain. Thus, pigs weaned at 24 days and supplemented with Biofeed Plus CT grew more quickly during the third week (559 v. 460 g/day), whereas the converse was true for pigs weaned at 14 days (286 v. 334 g/day). Also, enzyme-supplemented boars grew better over this period (457 v. 371 g/day), whereas the converse was true, for gilts (388 v. 423 g/day). In conclusion, these data clearly indicate that the greatest determinant of post-weaning performance under the present conditions was the age of the pigs at weaning. Dietary enzyme supplementation appeared most efficacious in boars weaned at an older age, although benefits did not become apparent until 2 weeks after weaning.