Li, H.-t., Wang, L., Liu, D. and Yang, X.-q. 2012. Characterization and functional significance of polymorphisms in porcine Toll-like receptor (TLR) 5 gene. Can. J. Anim. Sci. 92: 409-415. Toll-like receptor (TLR) 5 plays an important role in host defenses by recognizing bacterial flagellin and signaling to initiate immune responses. Polymorphisms in the TLR5 gene have a profound influence on receptor function and host susceptibility/resistance to infectious disease, as suggested by studies in humans and other species. In the present study, we characterized polymorphisms and determined their functional significance in the porcine TLR5 gene. Four novel non-synonymous single nucleotide polymorphisms (SNPs), c.176C>T (p.R59M), c.902C>T (p.S301F), c.959T>A (p.F320Y), and c.1796C>T (p.T599M) (reference sequence: GenBank No. AB208697), were first identified by sequencing the complete coding sequences (CDS) of the TLR5 gene in the Min pig, an indigenous Chinese pig breed known for its high general resistance to disease. SNP c.1796C>T (p.T599M) is located in one of the six predicted N-glycosylation sites in the extracellular domain of the TLR5 protein. By measuring protein activation, as represented by nuclear factor κB activity, in transiently transfected PK-15 cells with TLR5 expression vectors carrying site-directed mutations, we demonstrated that the previously discovered SNP c.1205C>T, leading to the amino acid substitution of proline by leucine, attenuated the responses of the receptor to flagellin (P<0.01). Further functional investigation on SNP c.1205C>T is necessary to determine its possible role in disease susceptibility in pigs and may facilitate pig breeding aimed at improving disease resistance.

Li, J., Yuan, Q., Shen, J., Tao, Z., Li, G., Tian, Y., Wang, D., Chen, L. and Lu, L. 2012. Evaluation of the genetic diversity and population structure of five indigenous and one introduced Chinese goose breeds using microsatellite markers. Can. J. Anim. Sci. 92: 417-423. The aim of this study was to determine the genetic diversity and evolutionary relationships among five indigenous Chinese goose breeds and one introduced goose breed using 29 microsatellite markers. A total of 334 distinct alleles were observed across the six breeds, and 45 of the 334 alleles (13.5%) were unique to only one breed. The indigenous geese showed higher diversity in terms of the observed number of alleles per locus (4.48-5.90) and observed heterozygosity (0.46-0.53) compared with the introduced breed (3.97 and 0.29, respectively). The pairwise genetic differentiation (F_ST) between the six goose breeds ranged from 0.04 between Panshi Grey goose (PS) and Yongkang Grey goose to 0.47 between PS and Landes goose; similarly, Nei's genetic distance varied between 0.25 and 0.75. However, the F_ST between the indigenous Chinese goose breeds was very small. In addition, genetic distance estimate, phylogenic, and cluster analyses of the genetic relationships and population structure revealed that some indigenous goose breeds had hybridized more frequently, resulting in a loss of genetic distinctiveness.

Wang, D., Lu, L., Tian, Y., Li, J., Shen, J., Tao, Z., Li, G. and Xu, N. 2012. Molecular cloning, characterization and expression patterns of heat shock protein 60 (HSP60) in the laying duck (Anas platyrhynchos). Can. J. Anim. Sci. 92: 425-432. In the present study, we cloned and characterized the HSP60 cDNA from Anas platyrhyncho (designated as ApHSP60) using a combination of homology and rapid amplification of cDNA ends (RACE). The full-length of ApHSP60 is 2027 bp in length, with an open reading frame of 1707 bp encoding a putative protein of 569 amino acids. Comparison of amino acid sequences of HSP60 revealed ApHSP60 is highly conserved, especially in the domains of classical HSP60 family signatures. ApHSP60 transcripts were at low expression levels throughout embryo development. ApHSP60 transcripts were constitutively expressed in all tested tissues of untreated laying duck, with a maximum level in the liver. Fluorescent real-time quantitative reverse transcription-polymerase chain reaction was applied to determine ApHSP60 expression after exposure to different thermal shocks. Under long term treatment with both 30°C and 35°C, ApHSP60 transcripts in heart and liver were significantly up-regulated. Otherwise, ApHSP60 transcripts were remarkably down-regulated in heart and liver under acute challenge with 40°C (a fatal temperature for laying duck). A time-dependent expression pattern of ApHSP60 was found in the recovery period after heat shock reaction. ApHSP60 expression levels in liver and heart were immediately up-regulated to the maximum at 1 h post-challenge, and then decreased to pre-challenge levels by 2 h and 3 h post-challenge, respectively. These results suggest that mRNA expression of the ApHSP60 gene is constitutive and inducible. Meanwhile, it plays an important role in response to heat stressors.

Lu, L., Gao, X., Li, Q., Huang, J., Liu, R. and Li, H. 2012. Comparative phosphoproteomics analysis of the effects of L-methionine on dairy cow mammary epithelial cells. Can. J. Anim. Sci. 92: 433-442. L-methionine is an essential amino acid that plays fundamental roles in protein synthesis. Many nuclear phosphorylated proteins such as Stat5 (signal transducer and activator of transcription 5) and mTOR (mammalian target of rapamycin) regulate milk protein synthesis. But a comprehensive understanding of transcriptional and posttranscriptional regulation of milk protein synthesis is lacking. In the current study, two-dimensional gel electrophoresis (2-DE)/MS-based proteomics analysis was used to identify phosphoproteins responsible for milk protein synthesis in dairy cow mammary epithelial cells (DCMECs). The effects of L-methionine on DCMECs were analyzed by CASY (Counter Analyser System) technique, reversed phase high performance liquid chromatography. The results showed that rate of cell proliferation and expression of β-casein were increased in DCMECs treated with 0.6 mM L-methionine for 24 h. Five proteins for which expression was significantly increased in DCMECs were selected, and their expression changes were verified by quantitative real-time PCR and Western blot analysis. The five up-regulated expressed phosphoproteins included Staphylococcal nuclease domain-containing protein 1(SND1), Septin-6, Glycyl-tRNA synthetase (GARS), Twinfilin-1 and eukaryotic elongation factor1-beta (eEF1B). This study revealed that availability of L-methionine influences the levels of nuclear phosphorylated proteins of DCMECs which opens a new avenue for the study of the molecular mechanism linking to milk protein synthesis.

Ilse, B. R., Anderson, V. L., Buchanan, D. S., Odde, K. G., Lardy, G. P. and Vonnahme, K. A. 2012. Short Communication: Growth and attainment of puberty in calves from cows supplemented with linseed meal during late gestation and early lactation. Can. J. Anim. Sci. 92: 443-447. To test the objective that a linseed meal (LSM) supplement in beef cows during late gestation and early lactation would impact offspring growth performance, steer carcass composition, and attainment of puberty in heifer calves, multiparous beef cows received either LSM or a control supplement for the last 60 d of gestation (exp. 1; n=72) or during the first 60 d of lactation (exp. 2; n=91). In both experiments, birth weight, weaning weight, and ADG of calves were not affected (P>0.31) by LSM supplementation. There was no effect (P>0.09) of supplementation on carcass characteristics of steer progeny fed to market weight. In exps. 1 and 2, attainment of puberty in heifer calves was not influenced (P>0.58) by supplement type. Linseed meal supplementation during late gestation or early lactation does not appear to affect calf growth, onset of puberty in heifer calves, or steer carcass quality.

López-Campos, Ó., Basarab, J. A., Baron, V. S., Aalhus, J. L. and Juárez, M. 2012. Reduced age at slaughter in youthful beef cattle: Effects on carcass merit traits. Can. J. Anim. Sci. 92: 449-463. Two-hundred and twenty-four spring-born British×Continental crossbred steers were used in a 2-yr project to evaluate the effect of production system (calf-fed vs. yearling-fed) and its interaction with breed cross and hormone implant strategies, with and without β-adrenergic agonist on carcass characteristics. Carcasses from yearling-fed steers were 32% heavier (P<0.001), resulting in higher (P<0.05) dressing percentages, grade fat and rib-eye (longissimus thoracis) area (REA) (1.1, 32 and 10%, respectively). However, despite being lighter, the estimated lean yield percentage was 3% greater (P=0.010) in carcasses from calf-fed steers. No difference (P>0.05) was observed for marbling scores between production systems. Use of hormonal implants increased (P<0.001) weights of live animals and carcasses (7 and 9%, respectively). However, non-implanted yearling-fed steers had the lowest proportion of Canada Quality Grade A and the highest proportion of Canada Quality Grade AAA carcasses (P<0.001). Moreover, the observed increase (P=0.016) in marbling scores (up to 37%) from British cross-bred steers disappeared with the use of implants. The only effect observed on carcass traits from the use of β-adrenergic agonists was an increase of 6% in REA (P=0.032). The main production system effect observed for carcass composition was a lower (P=0.008) proportion of bone in carcasses from yearling-fed steers. The use of hormonal implants increased (P<0.001) the proportion of lean and decreased (P=0.019) the proportion of fat (P<0.05). Overall carcass composition of steers with large Continental influence (>50%) had a higher proportion of lean and bone and a lower proportion of fat than carcasses from 50-75% British steers (P<0.001), which was also reflected in the composition of several individual primal cuts (e.g., rib, short-loin, flank, chuck and plate). The interactions amongst production systems and the other production factors studied were minimal. Therefore, despite expected differences in carcass size, reducing age at slaughter did not have a negative impact on Canadian beef carcass traits.

Fortier, M. P., Saucier, L. and Guay, F. 2012. Effects on microbial quality of fresh pork loin during storage from oregano oil and cranberry pulp diet supplementation in pigs. Can. J. Anim. Sci. 92: 465-471. Oregano oil and ground cranberry pulp supplements were added to the diets of finishing pigs to determine their antimicrobial effects on fresh loin during storage at 2±1°C. Two doses of oil (250 and 500 mg kg^-1) and three doses of cranberry (5, 10 and 20 g kg^-1) were tested according to a factorial experimental design. The control group did not receive any supplements. The meat was vacuum packed and analyzed after 0, 23, 45 and 60 d. Samples were re-packaged under aerobic conditions after 0 or 23 d and analyzed after 4, 8 and 12 d. Microbial analysis was performed periodically throughout the experiment. Initial cell counts were below detection level for total aerobic mesophilic (TAM) (<10² cfu g^-1), Pseudomonas spp. (<10² cfu g^-1), presumptive lactic acid bacteria (LAB) (<10² cfu g^-1), and Escherichia coli and coliform counts (<10¹ cfu g^-1). No significant difference in TAM counts was observed between all of the six different treatments and the control group except for samples packaged at day 0 under aerobic conditions after 12 d of storage where a significant effect of the supplementation was observed (P<0.03). Under anaerobic conditions, LAB were not affected and remained the predominant microflora despite antimicrobial treatments.

Faridi, A., Golian, A. and France, J. 2012. Evaluating the egg production of broiler breeder hens in response to dietary nutrient intake from 31 to 60 weeks of age through neural network models. Can. J. Anim. Sci. 92: 473-481. The aim of this study was to evaluate the response of broiler breeder hens in terms of egg production to dietary nutrient intake. Using neural network (NN) models and breaking down the collected data from 98 commercial broiler breeder houses into 3-wk intervals, 10 NN-based models were developed from 31 to 60 wk of age. The data lines were divided into two random subsets of training (n=64) and testing (n=34) sets. The variables of interest for developing the models were metabolizable energy (ME; kcal bird^-1 d^-1), and crude protein (CP), total sulphur amino acids (TSAA), lysine (Lys), calcium (Ca) and available phosphorus (AP), all in g bird^-1 d^-1. The random optimization algorithm was applied to the constructed models to find the optimal level of the input variables which maximized egg production during the different intervals. The high R² values in all the developed models for both the training and testing sets indicate the accuracy of NN-based models in estimating egg production. The optimization results revealed that breeder hens consuming 485, 473, 471, 466, 460, 452, 448, 442, 437 and 445 kcal of ME bird^-1 d^-1 showed the highest egg production during the 10 consecutive 3-wk intervals from 31 to 60 wk of age, respectively. Moreover, the optimal performance of hens required the following average intakes from 31 to 60 wk of age (g bird^-1 d^-1): CP: 23.7; TSAA: 1.05; Lys: 1.07; Ca: 4.91; and AP: 0.58. The results show that energy (kcal bird^-1 d^-1) and other nutrient requirements (g bird^-1 d^-1) of broiler breeder hens from 31 to 60 wk of age do not change in consort together with age; therefore using different diets with different dietary nutrient levels during the production cycle may help the nutritionists better meet the requirements of broiler breeder hens. Based on the present study, it appears that company guideline recommendations may underestimate the nutrient requirements of hens during these weeks when egg production is declining gradually.

Perttula, J. and Bédécarrats, G. Y. 2012. Blindness in Smoky Joe roosters results in advanced sexual maturation. Can. J. Anim. Sci. 92: 483-491. In chickens, an increase in photoperiod activates the hypothalamo-pituitary gonadal axis resulting in sexual maturation. Although it is well established that light can directly stimulate the hypothalamus, the relative contribution of the eye in the control of reproduction is still controversial. Using a genetically blind line of chickens (Smoky Joe), we investigated the relative importance of the retina of the eye in sexual maturation in roosters. Furthermore, to evaluate the effect of photostimulation, three generations of blind and sighted Smoky Joe roosters were utilize. Generation 1 (G1) was photostimulated at 17 wk of age, while generation 2 (G2) was left un-photostimulated and generation 3 (G3) was photostimulated at 12 wk of age. Blind roosters in G1 and G2 matured between 17 and 19 wk of age (testicular weight, comb length) independently of photostimulation whereas maturation of sighted animals was significantly delayed in G2. However, this advanced sexual maturation was no longer evident when birds were stimulated at 12 wk of age. Blind roosters in G2 showed advanced spermatogenesis when compared with sighted animals. No significant difference in plasma testosterone levels was observed for any of the three generations. In conclusion, although still photosensitive, blind rooster sexually matured spontaneously earlier than their sighted counterpart.

Bernier, J. N., Undi, M., Plaizier, J. C., Wittenberg, K. M., Donohoe, G. R. and Ominski, K. H. 2012. Impact of prolonged cold exposure on dry matter intake and enteric methane emissions of beef cows overwintered on low-quality forage diets with and without supplemented wheat and corn dried distillers' grain with solubles. Can. J. Anim. Sci. 92: 493-500. This study was conducted to determine the impact of prolonged cold exposure on dry matter intake (DMI) and enteric methane (CH₄) emissions of overwintering beef cows consuming low-quality forage with and without supplemented protein in the form of dried distillers' grain with solubles (DDGS). The study was carried out with 30 mature, dry, open beef cows (663±52.9 kg) that were fed a low-quality (deficient CP, 6.0% CP) forage (control), low-quality forage supplemented with 10% DDGS (sufficient CP, 8.7% CP; DDGS10) or 20% DDGS (excess CP, 11.6% CP; DDGS20). Carrying out the study from October through February allowed assessment under thermal neutral and prolonged cold conditions typical of the prairie region of Canada (Manitoba, Alberta and Saskatchewan). Average minimum and maximum daily temperatures were 2.7 and 13.8°C in the thermal neutral period, and -23.5 and -11.0°C in the prolonged cold period, respectively. When no protein supplements were offered, cows exposed to prolonged cold consumed less (P=0.01) forage than when exposed to thermal neutral conditions. Enteric CH₄ emissions, when measured as litres per day, were not influenced (P>0.05) by dietary protein supplementation, averaging 285.6±11.71, 311.9±11.49 and 282.6±13.02 L d^-1 for cows fed control, DDGS10, and DDGS20 diets, respectively. When expressed as a percentage of energy consumed, cows consuming low-quality forage supplemented with 20% DDGS produced 18.5% less (P=0.01) enteric CH₄ relative to cows consuming the low-quality forage only, with emissions of 5.3±0.38 and 6.5±0.33% GEI, respectively. Mature beef cows maintained at the same physiological status and dietary regime produced 26.8% less (P=0.001) enteric CH₄ (7.1±0.30 vs. 5.2±0.26% GEI) under prolonged cold as compared with thermal neutral conditions. Based on these results, enteric CH₄ emissions for the Canadian cow herd that is overwintered outdoors may be overestimated using current International Panel on Climate Change (IPCC) methodology.

Friedt, A. D. and McKinnon, J. J. 2012. Short Communication: Effects of feeding wheat bran and condensed liquid whey in diets of growing cattle. Can. J. Anim. Sci. 92: 501-504. Wheat bran (WB) derived from abrasion milling prior to ethanol production was evaluated in backgrounding diets for steer calves alone or in combination with condensed liquid whey (CLW) as a partial replacement for barley grain. There was no effect of CLW on any performance parameter, nor was any WB×CLW interaction detected. Average daily gain was not affected (P>0.05) by WB inclusion; however, dry matter intake of cattle fed WB was higher (P<0.01) than that of cattle fed the barley-based diet. Gain:feed and estimated diet NE_g content were decreased (P<0.01) by WB inclusion. Ultrasound carcass traits were not (P>0.05) affected by treatment. These results indicate that WB can replace barley grain at levels up to 28% of the diet DM without impacting ADG or composition of gain in growing calves. However, calculated NE_g of WB-based diets is lower than that of barley-based diets, thus calves must consume more feed DM to maintain similar gains.

Woyengo, T. A., Akinremi, O. O., Rossnagel, B. G. and Nyachoti, C. M. 2012. Performance and total tract nutrient digestibility of growing pigs fed hulless low phytate barley. Can. J. Anim. Sci. 92: 505-511. An experiment was conducted to determine the performance and nutrient digestibility of growing pigs fed hulless low phytate (HLP) barley without or with phytase for 28 d. Twenty-four growing pigs (average initial body weight=25.3 kg) were fed three diets in a completely randomised design. The diets included a regular-hulled barley-based diet, and a HLP barley-based diet without or with phytase at 500 phytase units kg^-1. Pigs fed the HLP barley-based diet without phytase had greater (P<0.05) average daily gain (0.911 vs. 0.717 kg), and apparent total tract digestibility of dry matter, energy, P, Mg, and Na were higher (P<0.05) than the regular barley-based diet. Supplementation of phytase to the HLP barley-based diet resulted in improved (P<0.05) feed conversion efficiency (0.506 vs. 0.547 kg kg^-1), and apparent total tract digestibility of N, P and K. In conclusion, pigs fed the HLP barley-based diet had higher growth performance and nutrient digestibility than those fed the regular-hulled barley-based diet, indicating that the HLP barley is a better source of nutrients for pigs than regular barley. Phytase supplementation to the HLP barley-based diet can result in a further increase in nutrient utilisation by pigs.

Quiniou, N., Quinsac, A., Crépon, K., Evrard, J., Peyronnet, C., Bourdillon, A., Royer, E. and Etienne, M. 2012. Effects of feeding 10% rapeseed meal (Brassica napus) during gestation and lactation over three reproductive cycles on the performance of hyperprolific sows and their litters. Can. J. Anim. Sci. 92: 513-524. Largely due to increased production of biodiesel, there is a greater availability of solvent-extracted rapeseed meal (RM) in France, making it competitive for feeding pigs. Nevertheless, the long-term effects of dietary glucosinolates (GSL) when feeding RM on sow reproductive and litter performance are a persistent concern to feed manufacturers. Four batches of 24 hyperprolific sows were fed to evaluate the effects of including 0 or 10% RM [14.5 µmol GLS g^-1 dry matter (DM) basis] in the gestation and lactation diets over three reproductive cycles. Intake of dietary GLS remained below 5 mmol d^-1 over the gestation period and averaged 8 mmol d^-1 over the lactation period, corresponding to less than 2 µmol GLS g^-1 DM basis. Lactation feed intake, sow body weight and backfat, and the length of the weaning-to-estrus interval were not different (P>0.05) between treatment groups. Sows fed diets with 10% or no RM farrowed 43.6 and 43.8 piglets over three reproductive cycles, respectively (P>0.05). Piglet weight at birth or weaning, survival and litter weight gain were not affected (P>0.05) by dietary RM inclusion. Similar (P>0.10) plasma thyroxin levels of sows and piglets indicated that thyroid function was not altered by RM inclusion. In conclusion, feeding gestation and lactation diets including 10% RM to hyper prolific sows over three parities was safe and did not affect sow longevity, reproductive or litter performance.

Sheppard, S. C. and Bittman, S. 2012. Farm practices as they affect NH₃emissions from beef cattle. Can. J. Anim. Sci. 92: 525-543. Beef cattle farms in Canada are very diverse, both in size and management. Because the total biomass of beef cattle in Canada is larger than any other livestock sector, beef also has the potential for the largest environmental impact. In this study we estimate NH₃ emissions associated with beef cattle production across Canada using data on farm practices obtained from a detailed survey answered by 1380 beef farmers in 11 Ecoregions. The farms were various combinations of cow/calf, backgrounding and finishing operations. The proportion of animals on pasture varied markedly among Ecoregions, especially for cows and calves, and this markedly affected the estimated NH₃ emissions. The crop components of feed also varied among Ecoregions, but the resulting crude protein concentrations were quite consistent for both backgrounding and finishing cattle. Manure was stored longer in the west than in the east, and fall spreading of manure was notably more common in the west, especially when spread on tilled land. The estimated NH₃ emissions per animal were relatively consistent across Ecoregions for confinement production, but because the proportion of animals on pasture varied with Ecoregion, so did the overall estimated NH₃ emissions per animal. Temperature is a key factor causing Ecoregion differences, although husbandry and manure management practices are also important. Hypothetical best management practices had little ability to reduce overall emission estimates, and could not be implemented without detailed cost/benefit analysis.

Bach, S. J., Cook, S. R., Wang, Y., Stanford, K., Johnson, R. P. and McAllister, T. A. 2012. Short Communication: Escherichia coli O157 bacteriophages: lytic activity and effects on fermentation in ruminal batch culture. Can. J. Anim. Sci. 92: 545-550. The effect of three lytic Escherichia coli O157, rV5, wV8 and wV11 on in vitro pH, gas production and dry matter disappearance in bovine ruminal cultures were assessed. None of the bacteriophages altered any of the measured parameters in ruminal fluid from concentrate or forage-fed animals. All bacteriophages were able to persist in ruminal fluid from forage and concentrate-fed cattle over a 24-h period; however, lytic activity against E. coli O157:H7 in ruminal batch cultures was not evident.