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.

Influence of housing type and age in female pigs. 1. Effects on growth performance and fat deposition and distribution in the carcasses of female Large White × Landrace pigs grown from 5.5 to 120 kg liveweight

One hundred and sixty female Large White × Landrace pigs were obtained at 3 weeks of age, average liveweight (LW) 5.5 ± 0.08 kg, stratified on LW and allocated to four treatments in a factorial design that consisted of two housing treatments, conventional (C) or deep-litter (D), across two growth periods: early (3–13 weeks of age) and late (13–24 weeks of age). At 13 weeks of age eight pigs per treatment (n = 32) were slaughtered, and the remaining pigs (n = 128) moved to new pens where they remained until slaughter at 24 weeks of age. Moving pigs into a new housing system caused a growth reduction, as indicated by significantly lower LW (P = 0.003), compared with pigs that remained within the same housing system, regardless of whether the new system was C or D. Carcass composition results indicated that pigs finished in the D system (24 weeks of age) were not fatter than pigs raised in C housing, with pigs raised entirely in C housing tending to be the fattest (P = 0.090). There was an effect of housing on fat distribution within the carcass where pigs finished in D housing had significantly less fat in the belly primal compared with pigs finished in the C facilities (35.3 versus 31.2%, P = 0.030). These findings suggest that the strategy of moving pigs from D housing to C housing for finishing, to reduce carcass fatness and improve pig growth performance, was not successful as pigs were fatter, lighter and less efficient than pigs of the same age housed in D from wean to finish.

Influence of housing type and age in female pigs. 2. Effects on biochemical indicators of fat metabolism and the fatty acid profile of belly fat and back fat depots

Weaning pigs into deep-litter (D) housing systems and then moving them into conventional (C) housing facilities affects the growth paths of the pigs and can result in differences in carcass composition which may be explained by altered fat metabolism. To examine this proposition experimentally, 160 female Large White × Landrace pigs were obtained at 3 weeks of age, average liveweight 5.5 ± 0.08 kg and were stratified by weight to four treatments. The treatments consisted of two housing treatments, C or D, across two growth periods: (i) early (3–13 weeks of age); and (ii) late (13–24 weeks of age). At ~13 weeks of age eight pigs per experimental treatment (n = 32) were slaughtered and the remaining pigs (n = 128) moved to new pens where they were housed until slaughter at ~24 weeks of age. To 13 weeks of age, the effect of housing type on lipogenesis did not reach significance (P > 0.05). At 24 weeks of age there were some treatment differences in fatty acid profile (P ≤ 0.05) and the concentration of plasma glycerol (P = 0.002) and non-esterified fatty acids (P = 0.019). There were trends for lipogenic enzyme activity to differ between treatments also (P < 0.100). Results suggested fat deposition was lower in D-finished pigs compared with C-finished pigs, rejecting the hypothesis that D-finished pigs would be fatter. However, most of the differences in the biochemical measurements were explained by the significant reduction in growth that occurred when pigs changed housing environments, rather than as an effect of the housing environment itself. Indicators of lipogenesis suggested that lipogenic rate was lowest in pigs moved from C to D housing compared with other treatment groups that had remained within the same housing, C or D, throughout the experiment or had moved from D housing to C housing at 13 weeks of age.

Effects of continual fluctuation in feed intake on growth performance response and carcass fat-to-lean ratio in grower-finisher pigs

An experiment was conducted to examine the effect of continual fluctuations in feed intake on grower-finisher pig growth performance and carcass fat-to-lean ratio (F:L). Sixty individually housed female pigs (Landrace x Large White) with initial BW of 29.8 +/- 0.4 kg were randomly allocated to 1 of 4 feeding regimens (n = 15): 1) ad libitum throughout (AL); 2) 85% of the mean intake of the AL group during the previous week (R); 3) 70% of the mean intake on 1 d, and on the following day, 100% of the amount consumed by the AL group during the preceding week, with this pattern repeated every 2 d throughout (D); and 4) 70% of the mean intake for 3 consecutive days, and 100% of the amount consumed by the AL group for the next 3 d, with this pattern repeated throughout the experiment (3-D). Pigs receiving each treatment were fed the same diets during the weaner (10 to 20 kg), grower (20 to 50 kg), finisher 1 (50 to 70 kg), and finisher 2 (70 kg to slaughter at approximately 104 kg) growth phases. Pigs receiving fluctuated feed intake either by the D or 3-D feeding regimen showed a pattern of growth similar to that of pigs on the R feeding regimen. Pigs on the R and 3-D regimens were lighter at 28 d (P < 0.05) and pigs on the R, D, and 3-D regimens were lighter at 63 d (P < 0.05) than pigs on the AL regimen. Pigs on the R, D, or 3-D feeding regimens had a greater G:F between 15 to 42 d of the experiment than pigs fed AL throughout (P < 0.05). The R, D, and 3-D feeding regimens seemed to have some effect on carcass weight and dressing percentage, and pigs had a decreased P2 (located 65 mm from the midline of the carcass at the last thoracic rib) backfat depth (P < 0.05) compared with pigs fed AL. Pigs on the AL and 3-D feeding regimens had thicker subcutaneous fat at the last lumbar vertebrae on the dorsal edge of the loin than pigs on the R feeding regimen (P < 0.05). Carcass and visceral fat content and the F:L in the carcass and primal cuts, as measured by dual energy x-ray absorptiometry, were not different among treatments. However, pigs on the AL and 3-D feeding regimens had decreased estimated bone content in the carcass compared with pigs on the R and D feeding regimens (P < 0.05). The results indicated that continual fluctuation in feed intake either every other day or every 3 d had minimal effects on growth and carcass F:L compared with pigs fed the same restricted amount throughout the experiment.

The causes of seasonal variation in backfat thickness of pigs in Western Australia

Anecdotal observations suggest that pigs get fatter at certain times of the year. Abattoir data from a major Western Australian genotype were investigated to determine whether there is seasonal variation in P2, and if so, what factors may contribute to this. In the data collected, it was found that pigs were fattest during spring and leanest during autumn. At initial observation, variation in carcass weight (hence liveweight at slaughter) appeared to explain much of the variation in carcass fatness. However, fitting a linear mixed model to the P2 data, adjusted for carcass weight, indicated that there was also a significant effect of season on carcass quality.