Alain Giguère

The effects of handling and group size on welfare of pigs in lairage and their influence on stomach weight, carcass microbial contamination and meat quality

At unloading and on the way to stunning, 800 barrows were exposed to either gentle handling (GH: slowly with a plastic board or whip) or rough handling (RH: quickly with an electric prod). Pigs were kept in large or small groups (30 or 10 pigs) during lairage. Compared with GH, RH increased climbing (P < 0.05), slipping (P < 0.01) and turning around (P < 0.001) behaviours during unloading, and climbing (P < 0.05) on the way to stunning. RH also reduced drinking behaviour during lairage (P < 0.01). Pigs kept in large groups were observed more often standing (P < 0.05) and fighting (P < 0.001) than pigs kept in small groups, but, in contrast, had a slightly lower level of urinary cortisol at slaughter. Stomach weight and microbial contamination at slaughter were not affected by treatments. RH tended to increase skin bruise score on the carcass (P < 0.06) and produced more exudative meat (P < 0.05). In conclusion, the response of pigs to the two specific stressors applied prior to slaughter in this study did...

Effect of feed texture, meal frequency and pre-slaughter fasting on carcass and meat quality, and urinary cortisol in pigs.

Carcass and meat quality traits, and urinary cortisol variation was studied in 96 barrows assigned to the following treatments: feed texture (FT; mash vs. pellets), meal frequency (MF; 2 vs. 5 meals per day) and fasting time (F; 4, 14 and 24h) according to a 2×2×3 factorial design. Pigs fed mash, receiving feed five times a day and fasted for 24h before slaughter had lower carcass dressing yield (P<0.001). A higher (P<0.05) bruise score was found on carcasses from pigs fasted for 14 and 24h and fed either pelleted or mashed feed five times per day. The pH(u) value in the Longissimus muscle increased (P<0.05) with increasing fasting time, whereas in the Adductor muscle it was higher (P<0.05) in pigs fed with pellets in two meals per day and fasted for 24h. Urinary cortisol tended to be higher in pigs fasted for 14h compared to those fasted for 4 (P=0.10) and 24h (P=0.06). The results of this study show a significant influence of pellet feeding on carcass yield in fasted pigs, while the effects of pre-slaughter fasting time on meat quality traits were limited.

Effects of folic acid and vitamin B12 supplements on folate and homocysteine metabolism in pigs during early pregnancy

The present experiment aimed to determine the effects of supplements of folic acid (FA) alone or in combination with vitamin B12 on folate and homocysteine metabolism in gestating nulliparous Yorkshire-Landrace (YL) and multiparous Landrace (LD) occidental sows and multiparous Chinese Meishan-Landrace (ML) sows. LD sows were randomly assigned to two treatments: 0 or 15 mg FA/kg diet while YL and ML sows were assigned to three treatments: 0 mg FA/kg diet, 15 mg FA/kg or 15 mg vitamin B12/kg diet. Supplements were given from the oestrus preceding insemination up to slaughter on day 15 of gestation. At slaughter, a uterine flush was collected to determine uterine contents of homocysteine, methionine, tetrahydrofolate (THF), 5-methyl-THF, pyridoxal 5-phosphate (P5P) and vitamin B12. Blood samples were taken at first oestrus, at insemination and on days 5, 10 and 15 of gestation to determine plasma concentrations of homocysteine, methionine, THF, 5-methyl-THF, P5P, vitamin B12 and relative total folate-binding capacity. In occidental sows (YL and LD), the FA supplement tended to decrease uterine flush content of homocysteine (P=0.06) and concentrations of plasma homocysteine (P=0.09). Nulliparous YL sows had lower concentrations of plasma homocysteine, methionine, THF and 5-methyl-THF (P<0.05) than multiparous LD sows. Multiparous ML and LD sows had similar concentrations of plasma THF, 5-methyl-THF, methionine and vitamin B12, but ML sows had lower concentrations of plasma homocysteine (P<0.05). The vitamin B12 supplement increased concentrations of plasma vitamin B12 (P<0.05) both in multiparous ML and nulliparous YL sows, but had no effect on the composition of either uterine flush or plasma. The present results showed also that sows had a low vitamin B12 status (<200 pg/ml) and high circulating homocysteine levels (>15 microm) during the first 15 d of gestation. Furthermore, the vitamin B12 content in uterine secretions represented between 180 and 300 % of the total content in plasma. The low plasma concentrations of homocysteine in multiparous ML sows suggest a more efficient remethylation pathway which may not be dependent upon dietary supply of FA or vitamin B12. In nulliparous YL sows, low concentrations of both homocysteine and methionine suggest that the methionine requirement for protein deposition might have reduced the amount of methionine available for the methylation pathway. The results of the present experiment suggest that the reduction of uterine homocysteine may be an important aspect of the role of FA supplement on the uterine environment in occidental sows. The presence of high levels of vitamin B12 in uterine secretions merits further investigation in relation to embryonic development.

Reproductive performance and uterine prostaglandin secretion in gilts conditioned with dead semen and receiving dietary supplements of folic acid

The effects of dietary supplements of folic acid at 0 (F−) or 15 ppm (F+) and of conditioning the uterus (C+) or not (C−) with an intrauterine infusion of dead semen on embryonic survival and prostaglandin E2 (PGE2) concentrations in the allantoic fluid on day 30 of gestation were studied. Sixty-four F1 crossbred gilts (Yorkshire × Landrace) were used in a 2 × 2 factorial design. The initiation of folate supplementation and the intrauterine infusion of dead semen were done at the estrus preceding the fertile mating. Folate status in serum was lower in F+ gilts than in F− gilts during the estrus cycle (folic acid × period interaction, P ≤ 0.007). Conditioning increased ovulation rate in F− gilts while it tended to decrease it in F+ gilts (interaction folic acid × conditioning, P ≤ 0.03). A similar interaction (P ≤ 0.02) was observed on the number of presumably live embryos at 30 d of gestation. Mean PGE2 concentration in the allantoic fluid was not affected by treatments (P ≥ 0.44), but the frequency of so...

Effect of feed texture, meal frequency and pre-slaughter fasting on behaviour, stomach content and carcass microbial quality in pigs

In this study, behaviour in lairage, weight and composition of stomach contents and carcass microbial contamination were studied in 96 barrows assigned to the following treatments: feed texture (FT; mash vs. pellets), meal frequency (MF; 2 vs. five meals per day) and fasting time (WT; 4, 14 and 24 h) according to a 2 × 2 × 3 factorial design. Pigs fed two meals had heavier stomach weights at slaughter than those fed five times per day (P = 0.01). An interaction was found between WT and FT (P = 0.002) for stomach weight. With respect to the contamination of the mouth, total aerobic mesophilic counts were higher than 104 cfu cm-2 but not significantly different between treatments. Coprophagy behaviour in lairage was not correlated with mouth contamination at slaughter. The treatment resulting in the lowest Escherichia coli counts on the thoracic area was feeding the pigs pellets five times per day followed by a 24-h fast. In contrast, the highest E. coli counts were observed in pigs fed mash five times per ...

Methionine, folic acid and vitamin B12 in growing-finishing pigs: Impact on growth performance and meat quality

Growth performance, metabolic variables, and meat quality were measured in 78 growing-finishing pigs using supplements of 0 (C), or 0.2% of DL-methionine (M), and three combinations of folic acid [mg/kg] and cyanocobalamin [μg/kg], respectively 0 and 0 (V0), 10 and 25 (V1), and 10 and 150 (V2) in a 2 × 3 factorial arrangement. Feed conversion was lower (p = 0.05) in M than in C pigs during the growing period (0–4 weeks). Both V1 and V2 treatments increased plasma vitamin B12 (p < 0.01) and decreased plasma homocysteine (p < 0.01). Plasma 5-methyl-tetrahydrofolates were the lowest, highest and intermediate in V0, V1 and V2 pigs (p < 0.04), respectively. In V2 meat, folates were 32% higher, vitamin B12, 55% higher and homocysteine, 28% lower than in V0 (p < 0.01). Oxidative stability of the fresh meat was similar among treatments during a storage period of 42 days. Therefore, methionine supplements improved growth performance during the growing period. Vitamin supplements interacted with the methionine cycle pathway, increased vitamin content of pork meat but did not improve oxidative stability of the fresh meat during storage.

Effect of folic acid plus glycine supplement on uterine prostaglandin and endometrial granulocyte-macrophage colony-stimulating factor expression during early pregnancy in pigs.

The objective was to determine the effects of folic acid+glycine supplement on uterine metabolism of prostaglandin and mRNA expression of endometrial granulocyte-macrophage colony-stimulating factor (GM-CSF) in nulliparous (NYL) and multiparous Yorkshire-Landrace (YL) sows, and in multiparous Meishan-Landrace sows (ML). In each of these three groups, sows were randomly assigned to two treatments: 15 ppm folic acid+0.6% glycine or no supplement. The dietary supplement was given from the estrus before mating to slaughter on Day 25 of pregnancy. At slaughter, endometrial tissue was collected to determine endometrial expression levels of GM-CSF mRNA, cyclooxygenase-1 (COX1) and -2 (COX2) and to evaluate in vitro endometrial secretion of prostaglandin E2 (PGE2) secretion. Allantoic fluid samples were also collected to determine the concentration of PGE2, prostaglandin F2alpha (PGF2alpha), estradiol-17beta (E2), progesterone (P4), and transforming-growth factor-beta2 (TGF-beta2). The allantoic contents of PGF2alpha, E2 and P4, and endometrial in vitro secretion of PGE2 were not significantly influenced by the folic acid+glycine supplement. The folic acid+glycine supplement tended (P<0.07) to increase allantoic content of PGE2 and TGF-beta2 in all sows and increased (P<0.05) endometrial expression of COX2, especially in NYL sows. The endometrial expression of COX1 was decreased (P<0.05) by folic acid+glycine supplement, especially in multiparous YL sows. The allantoic contents of PGE2 and PGF2alpha were not significantly affected by sow type. However, NYL sows had higher (P<0.05) endometrial in vitro secretion of PGE2 and allantoic content of P4 than multiparous YL and ML sows. The allantoic content of E2 was also higher (P<0.05) in NYL sows than in multiparous ML sows only. The allantoic content of TGF-beta2 was lower (P<0.05) in multiparous ML than in multiparous YL only sows. Finally, in YL and NYL sows, folic acid+glycine supplement decreased (P<0.05) the endometrial expression of GM-CSF but not in ML sows. In summary, folic acid+glycine supplement altered endometrial expression of GM-CSF and uterine metabolism of prostaglandins during the post-attachment period of porcine embryos but some of these effects were manifest only in Meishan and nulliparous sows.

Rapid, sensitive and versatile determination of selenium in different biological samples

The reliable assessment of selenium in biological samples is generally technically difficult to achieve and requires a large amount of material. The described fluorometric method was validated using certified standard material of Durum Wheat Flour, Bovine Muscle Powder, Whole Egg Powder and serum and was tested on pig whole blood and fresh egg. The technique was found to be fast, sensitive and robust for a reliable determination of Se in small amounts (< 50 mg or 100 µL) of biological samples. Key words: Selenium, analysis, biological samples

Some aspects of the pyridoxine (vitamin B6) requirement in weanling piglets.

Four trials were carried out to determine the optimal level of dietary pyridoxine (vitamin B6) and its interaction with riboflavin (vitamin B2) in early-weaned piglets. In Trial 1, twelve piglets were tube-fed graded supplements of B6, 0, 10, 50 or 100 mg/kg. The level of 50 mg/kg maximized B6 in red blood cells (P<0.05). In Trial 2, thirty-six piglets were tube-fed with four combinations of B6 (0 v. 50 mg/kg) and B2 (0 v. 25 mg/kg). The B6 supplement increased (P<0.01) B6 in red blood cells. C-peptide and insulin responses to intravenous glucose tended (P<0.08) to or decreased (P<0.03) with B2 while no effect was observed on glucose. After gastro-enteral glucose, dietary B2 depressed C-peptide and insulin responses in B6-unsupplemented piglets and increased them in B6-supplemented piglets (P<0.03). The glucose response tended to be higher in B6-supplemented piglets (P<0.06). Trials 3 and 4 were carried out in commercial conditions using either B6 and/or B2 supplements given during 2 weeks after weaning (Trial 3) or a B6 supplement alone (50 mg/kg) given between 2 (weaning) and 10 weeks of age. Despite a marked and persistent increase (P<0.01) of B6 in red blood cells in B6-supplemented piglets, the effect on growth performance was either none (P>0.39; Trial 3) or marginally lower (<-2 %; P<0.03; Trial 4). In conclusion, it appears that a dietary supplement of 50 mg/kg B6 saturated the red blood cell pool in B6 and influenced, along with B2, the glucose homeostasis through the entero-insular axis. Nevertheless, such metabolic effects are not reflected on growth performance.

Safety of dietary conjugated α-linolenic acid (CLNA) in a neonatal pig model.

The aim of the present study was to perform a short-term safety evaluation of dietary mono-conjugated α-linolenic acid isomers (CLNA; c9-t11-c15-18:3+c9-t13-c15-18:3) using a neonatal pig model. CLNA diet was compared with three other dietary fats: (1) conjugated linoleic acid (CLA; c9-t11-18:2+t10-c12-18:2), (2) non-conjugated n-3 PUFA and (3) n-6 PUFA. Thirty-two piglets weaned at 3 weeks of age were distributed into four dietary groups. Diets were isoenergetic and food intake was controlled by a gastric tube. Mono-CLNA diet did not significantly change body or organ weight, carcass composition and most biochemical parameters including; glucose, cholesterol, triglycerides, creatinine, blood urea nitrogen, hepatic enzymes and electrolytes levels in blood (P⩾0.09). Conversely, the n-3 PUFA composition of the brain, liver and heart decreased by 6-21% in the CLNA-fed group compared to animals fed nonconjugated n-3 PUFA (P<0.01). Responses to dietary treatments were tissue-specific, with the liver and the brain being the most deprived in n-3 PUFA. Our results support that short-term intake of mono-CLNA is safe in neonatal pigs but n-3 PUFA reduction in tissues deserves to be further investigated before using long-term nutritional supplementation in pigs and other animal models and before moving to clinical trials.