K. L. Moore

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.

Ractopamine supplementation increases lean deposition in entire and immunocastrated male pigs

Sixty entire male pigs (Large White × Landrace × Duroc crossbred) were individually reared from 45 to 114 kg liveweight in a 2 by 3 factorial experiment to determine the interactive effects of sex (entire male pigs v. male pigs immunologically castrated using Improvac with vaccinations administered at 13 weeks of age and 5 weeks before slaughter) and a ractopamine feeding program (constantly fed 0 or 5 ppm ractopamine for 26 days before slaughter v. a step-up program where 5 ppm of ractopamine was fed for 14 days followed by 10 ppm ractopamine for the final 12 days before slaughter) on growth performance, carcass composition and pork quality. Following the second vaccination, immunocastrated pigs ate more (P 0.05) in both entire and immunocastrated male pigs. The effects of dietary ractopamine and immunocastration were additive, such that pigs that were immunocastrated and received ractopamine grew 18% faster than control entire males. However, a step-up program of ractopamine supplementation did not provide further improvements in growth performance and carcass composition when compared with constant 5 ppm ractopamine supplementation. These findings indicate that ractopamine supplementation improved growth performance in entire and immunocastrated male pigs, thereby offering a means of improving growth performance of entire males without detrimental effects on pork quality.

The response of entire male and female pigs from 20 to 100-kg liveweight to dietary available lysine

TwoexperimentswereconductedtodeterminetheresponsesofentiremaleandfemalepigsoftheAustralianPig ImprovementCo.genotypetodietarylysine.InExperiment1,atotalof350(LargeWhite ·(Landrace ·Duroc))entiremale andfemalepigsweighing22.30.16kg(means.e.m.)wereusedina2by5factorialdesignwiththemaintreatmentsbeing sex(entiremalesandfemales)and fivelevelsofstandardisedilealdigestible(SID)lysinetodigestibleenergyratio(0.6,0.7, 0.8, 0.9 and 1.0 g SID lysine/MJ DE). In Experiment 2, a total of 420 (Large White · (Landrace · Duroc)) entire male and femalepigsweighing49.60.34kg(means.e.m.)wereusedina2by5factorialdesignwiththemaintreatmentsbeingsex (entire males and females) and five levels of SID lysine to MJ DE ratio (0.4, 0.5, 0.6, 0.7 and 0.8 g). From 20 to 50 kg liveweight(LW),entiremaleshadasimilaraveragedailygain(ADG),lowerfeedintake(FI,P <0.001)andbetterfeedtogain ratio(F:G,P <0.001)comparedwithfemales.From50to100kgLW,entiremaleshadahigherADG(P <0.001),similarFI and improved F:G ratio (P < 0.001) compared with females. Data were subjected to the quadratic response model to determine optimum SID lysine requirement for maximum ADG and minimum F:G for the weight ranges 20-35, 35-50, 50-65,65-80,and80to95kgLW.Formalepigs,maximumADGwasachievedatSIDlysinelevelsof1.00,0.87,0.72,0.67 and0.63g/MJDE,respectively.MinimumF:GwasachievedatSIDlysinelevelsof1.00,0.87,0.80,0.69and0.63g/MJDE fortherespectiveweightranges.Forfemalepigs,maximumADGwasachievedatSIDlysinelevelsof0.90,0.84,0.67,0.63 and0.58g/MJDE.MinimumF:GforfemaleswasachievedatSIDlysinelevelsof0.86,0.85,0.64,0.66and0.40g/MJDE for the respective weight ranges. The results suggest that this Australian genotype requires greater dietary SID lysine in the growing and finishing phase than the levels currently used by the Australian industry.

The interaction between ractopamine supplementation, porcine somatotropin and moisture infusion on pork quality

UNLABELLED Ninety six crossbred pigs were used in a 4×2×2 experiment to determine the influence of management strategy, moisture infusion and ageing on pork quality. The treatments were i) management strategy (MS) during the last 28days pre-slaughter ( CONTROL conventional diet; Ractopamine (Rac): porcine somatotropin (pST); and combined (Rac+pST): Rac for 28days and pST for the final 14days), ii) moisture infusion (MI) (0% and 10%) and iii) ageing period (24h and 7days). L* was decreased by pST and Rac+pST, followed by Rac and then the CONTROL MS. Shear force was increased by Rac and Rac+pST but not by either pST or the CONTROL MS. MI decreased L* and shear force while ageing for 7days increased L* and yellowness, and decreased drip loss and WB shear force. MI or ageing for 7days improved sensory pork quality. The results from this experiment indicated that as expected MI and ageing can be used to improve pork quality.

Boar taint, meat quality and fail rate in entire male pigs and male pigs immunized against gonadotrophin releasing factor as related to body weight and feeding regime☆

The objective of this experiment was to compare the pork quality of entire male pigs and pigs immunized against GnRF (IC males) at both light (64.8kg) and heavy (106kg) liveweights and two feeding regimes (restricted at 2.5 times maintenance and ad libitum). There was no difference in objective measurements (P>0.05) or eating pork quality (P>0.1) between entire male and IC males. Fail rates were reduced by 9.1% and 12% for pork from IC males for quality grade (P=0.007) and re-purchase intention (P=0.001), respectively, compared to pork from entire males. Skatole (P=0.001) and androstenone (P<0.001) levels in belly fat were higher in entire male than IC male pigs. In addition, 37.5% of the light entire male pigs fed ad libitum showed skatole levels that exceeded the sensory threshold of 0.2μg/g. This work confirms that immunization against GnRF is effective in eliminating boar taint and reducing pork quality fail rates by approximately 10% compared to pork from entire males.

Standardized ileal digestible lysine requirements of male pigs immunized against gonadotrophin releasing factor.

An experiment was conducted to determine the standardized ileal digestible (SID) Lys requirement of entire male and male pigs immunized against gonadotrophin releasing factor (GnRF; immunocastrates). A total of 420 entire male and immunocastrated (IC) male pigs weighing 60.1 kg BW (SEM 0.49) were used in a 2 × 5 factorial experiment with the main effects being gender (entire males or IC males) and 5 concentrations of SID Lys:DE ratio (0.32, 0.43, 0.54, 0.64, or 0.75 g SID Lys/MJ DE). The diets were fed for 6 wk until slaughter at 107.5 kg BW (SEM 5.72). Over the entire period, IC males had a greater ADG ( < 0.001), greater ADFI ( < 0.001), and lower G:F ( < 0.001) compared with entire males. Immunocastrated males had increased plasma urea nitrogen (PUN) concentrations compared with entire males from d 10 to 42 ( < 0.001 for all days). Plasma urea nitrogen concentration also increased as Lys concentrations increased from d 3 to 42 ( < 0.001 for all days). Using the linear-plateau model, the optimal ADG for entire males was achieved at SID Lys concentrations of 0.68, 0.62, 0.54, and 0.58 g/MJ DE whereas optimal G:F was achieved at SID Lys concentrations of 0.72, 0.60, 0.54, and 0.51 g/MJ DE for the time periods d 0 to 14, d 15 to 28, d 29 to 42, and d 0 to 42, respectively. For IC males, optimal ADG was achieved at SID Lys concentrations of 0.64, 0.43, 0.38, and 0.40 g/MJ DE whereas optimal G:F was achieved at SID Lys concentrations of 0.64, 0.43, 0.36, and 0.42 g/MJ DE for the same respective time periods. Using the quadratic polynomial model, maximum ADG for entire males was achieved at SID Lys concentrations of 0.62 and 0.58 g/MJ DE whereas maximum G:F was achieved at SID Lys concentrations of 0.59 and 0.68 g/MJ DE for d 29 to 42 and d 0 to 42, respectively. For IC pigs, maximum ADG was achieved at SID Lys concentrations of 0.69, 0.54, and 0.64 g/MJ DE whereas maximum G:F was achieved at SID Lys concentrations of 0.81, 0.54, and 0.64 g/MJ DE for d 0 to 14, d 29 to 42, and d 0 to 42, respectively. A solution could not be found using the quadratic polynomial model for entire males for d 0 to 14 for both ADG and G:F and for both entire males and IC males for d 15 to 28 within the range of Lys values tested. When both the growth performance and PUN values are considered, the results suggest that IC males show a response to dietary SID Lys similar to that of entire males for 2 wk after the second immunization against GnRF. After this, IC males have a lower requirement for SID Lys than entire males.

Blend-feeding or feeding a single diet to pigs has no impact on growth performance or carcass quality

A completely randomised block experiment was conducted using 216 female pigs (Large White × Landrace, six pigs/pen and 12 replicate pens/treatment), at an average liveweight (LW) of 22.6 kg ± 0.56 (mean ± s.e.m.), to examine the effect of feeding strategies on performance during the grower–finisher phase. Pigs were blocked and randomly allocated to the following treatments on the basis of initial LW: (1) phase-feeding: diets changed when the average LW of pigs in the pen reached 20, 50 or 80 kg; (2) blend: diets changed weekly to meet the requirements of the average LW of pigs in the pen and; (3) single: the same diet fed throughout (formulated to meet the requirements of the pig at 60 kg LW). The experimental diets were fed from 22 to 102 kg LW. Between 68 and 98 days of age, pigs fed the single diet grew more slowly (P 0.05) and there was no significant difference in carcass quality (P > 0.05) among treatment groups. However, it was 3.74% and 3.51% cheaper to use the blend- and single-diet feeding strategies, respectively, than it was to use a phase-feeding program (P = 0.002). The present experiment has shown that blend-feeding could be a strategy to reduce the cost of production. Feeding a single diet appears to have merit and may have appeal for certain circumstances; however, it would need to be investigated further before being implemented commercially.

Effect of feed restriction and initial body weight on growth performance, body composition, and hormones in male pigs immunized against gonadotropin-releasing factor

Pigs immunized against gonadotropin-releasing factor (GnRF) have increased carcass fatness compared to entire males; however, the timing of this increase in fatness after the second immunization against GnRF has not been determined. An experiment was conducted to identify and compare the growth performance, body composition, and physiological changes in immunocastrated males (IC males) at different BW and feeding levels. A total of 64 pigs were used in a 2 × 2 × 2 factorial experiment with the treatments being 1) sex (entire males or IC males), 2) initial BW (45.9 kg [light] or 78.3 kg [heavy]), and 3) feeding regime (2.5 times maintenance [restricted] or ad libitum). The pigs were individually housed, and the diets were fed for 4 wk after the second immunization against GnRF until slaughter at either 68.4 kg BW (light) or 105.8 kg BW (heavy). Immunocastrated males on a restricted feed intake had a lower ADG compared to entire males from d 15 to 28 and d 0 to 28 ( 0.011 and 0.011, respectively). Fat deposition was not affected by sex from d 0 to 14, but from d 15 to 28 IC males deposited 45 g/d more fat than entire males ( = 0.025). Immunocastrated male pigs fed ad libitum deposited 87 g/d more fat from d 15 to 28 than entire males fed ad libitum ( = 0.036). However, there was no difference in fat deposition between IC males and entire males when feed intake was restricted from d 15 to 28. Plasma urea nitrogen levels were greater in IC males compared to entire males from d 7 after the second immunization against GnRF ( 0.05 for d 7, 10, 14, 21, and 28). Plasma concentrations of IGF-1 were lower for IC males compared to entire males on d 3, 7, 10, and 28 ( 0.05 for all days). The following conclusions were made: 1) when pigs are immunized at a light BW (50 kg) and/or are on a restricted feed intake, they have a reduced propensity to deposit fat; however, the restriction in feed intake adversely affects growth rate. 2) The majority of fat deposition for males immunized at heavy BW (80 kg) occurs from d 15 to 28 after the second immunization against GnRF.

Supra-nutritional vitamin E supplementation for 28 days before slaughter maximises muscle vitamin E concentration in finisher pigs

A 4 × 3 factorial experiment (n=8 pigs per treatment combination) was conducted with 96 female Landrace × Large White pigs to examine the required level of dietary vitamin E and optimum feeding duration before slaughter to maximise muscle vitamin E content in the Longissimus thoracis et lumborum (LTL) muscle. The respective factors were four dietary levels of vitamin E (supplemented as dl-α-tocopheryl acetate; 35, 300, 500, and 700 IU/kg) and three feeding durations (14, 28 and 42 days before slaughter). Vitamin E concentration in the LTL was maximised at 6 mg/kg, which was achieved by feeding a 700 IU vitamin E diet for 28 days before slaughter (P<0.001). There was no further increase in the vitamin E content of the LTL by feeding the high vitamin E diet more than 28 days before slaughter.

The Effect of Lupinus albus and Calcium Chloride on Growth Performance, Body Composition, Plasma Biochemistry and Meat Quality of Male Pigs Immunized Against Gonadotrophin Releasing Factor

Simple Summary Pigs immunized against gonadotrophin releasing factor (immunocastrated (IC) males) have an increased feed intake, growth rate, back fat and fat deposition compared to entire males. It is desirable to develop management strategies to limit the increase in feed intake and fat deposition in IC males. This experiment used in-feed ingredients (Lupinus albus (albus lupins) or a combination of calcium chloride and sodium tri-polyphosphate (mineral salts)) to try to suppress the voluntary feed intake of IC male pigs and subsequently fat deposition. Mineral salts decreased feed intake with no effect on fat deposition while albus lupins reduced both feed intake and fat deposition in pigs. Abstract Two hundred and ninety-four pigs were used to assess the effect of two ingredients (Lupinus albus (albus lupins) or a combination of calcium chloride and sodium tri-polyphosphate (mineral salts)) on growth performance, body composition and objective meat quality of pigs immunized against gonadotrophin releasing factor (immunocastrates) and entire male pigs in the late finishing phase. Pigs fed mineral salts ate less feed than those fed the control diet with no effect on growth rate (p > 0.05), backfat (p > 0.05) or fat deposition (p > 0.05). Pigs fed albus lupins had a reduced feed intake (p < 0.001 for all time periods), lower growth rate (p < 0.001 for all time periods), lower backfat (p < 0.005) and decreased fat deposition (p < 0.001 for all time periods) compared to those fed the control diet or mineral salts. From day (d) 0–28 pigs fed mineral salts had a better feed conversion ratio (p = 0.001) than those fed albus lupins who in turn had an improved feed conversion compared to the control diet. Immunocastrates had thicker backfat than entire males at the end of the experiment (p < 0.001), however, feeding albus lupins to immunocastrated males reduced backfat thickness to similar to entire males fed the control diet (p = 0.01). With the exception of the increased muscle pH at 45 min post-exsanguination in mineral salts and albus lupins compared with the control diet (p = 0.03) there was no effect of diet on objective pork quality. Pork from IC males had a higher ultimate pH (p < 0.001), was lighter (L*; p = 0.003), more yellow (p = 0.008) and had a higher drip loss (p < 0.001) compared to entire males. Albus lupins show potential in reducing the increase in feed intake and backfat associated with immunocastration. Mineral salts may be useful in situations where a reduction in feed intake and an improvement in feed conversion is desired and reducing fat deposition is not the objective.