Journal of Animal Science and Biotechnology - Latest Articles

The biological stress of early weaned piglets

Joy Campbell — 2013-04-30T00:00:00Z

Pigs experience biological stress such as physiological, environmental, and social challenges when weaned from the sow. The process of weaning is one of the most stressful events in the pig’s life that can contribute to intestinal and immune system dysfunctions that result in reduced pig health, growth, and feed intake, particularly during the first week after weaning. Technological improvements in housing, nutrition, health, and management have been used to minimize some of the adverse effects of weaning stress, but a greater understanding of the biological impact of stress is needed to improve strategies to overcome weaning stress. The focus of this review paper is to briefly describe how the biological stress associated with weaning impacts intestinal morphology, structure, physiology, and intestinal immune responses that can impact subsequent production efficiencies such as growth, intake, morbidity, and mortality.

Use of a post-production fractionation process improves the nutritional value of wheat distillers grains with solubles for young broiler chicks

Philip Thacker — 2013-04-22T00:00:00Z

Background: Post-production fractionation of wheat distillers grains with solubles (DDGS) increases their crude protein content and reduces their fiber content. This experiment was conducted to determine the effects of fractionation of wheat DDGS on apparent total tract digestibility (ATTD) and performance when fed to broiler chicks (0--21 days). Methods: A total of 150, day-old, male broiler chicks (Ross-308 line; Lilydale Hatchery, Wynyard, Saskatchewan) weighing an average of 49.6 +/- 0.8 g were assigned to one of five dietary treatments in a completely randomized design. The control diet was based on wheat and soybean meal and contained 20% regular wheat DDGS. The experimental diets contained 5, 10, 15 or 20% fractionated wheat DDGS added at the expense of regular wheat DDGS. Results: The ATTD of dry matter and gross energy were linearly increased (P < 0.01) as the level of fractionated wheat DDGS in the diet increased. Nitrogen retention was unaffected by level of fractionated wheat DDGS (P > 0.05). Weight gain increased linearly (P = 0.05) as the level of fractionated wheat DDGS in the diet increased. Feed intake, feed conversion and mortality were unaffected by level of fractionated wheat DDGS in the diet (P > 0.05). Conclusions: Post-production fractionation of wheat DDGS improves their nutritional value by lowering their fiber content and increasing their content of crude protein and energy. These changes in chemical composition supported increased weight gain of broilers fed wheat DDGS.

The effects of dietary fiber level on nutrient digestibility in growing pigs

Wenjuan Zhang — 2013-04-15T00:00:00Z

The objective of this study was to investigate the effects of total dietary fiber level on nutrient digestibility and the relationship between apparent total tract digestibility of total dietary fiber, and soluble dietary fiber, insoluble dietary fiber and available energy. Sugar beet pulp was as the only fiber source. The experiment was designed as a 6 × 6 Latin square with an adaptation period of 7 d followed by a 5-d total collection of feces and urine. Feed intake tended to decrease (P =0.10) as total dietary fiber level increased. The apparent total tract digestibility of dry matter, crude protein and gross energy decreased (P <0.01) when total dietary fiber increased but the digestibility of soluble dietary fiber and insoluble dietary fiber increased (P <0.01). The digestible energy and metabolizable energy content of diets decreased (P <0.01) as the total dietary fiber increased.

Potential role of N-carbamoyl glutamate in biosynthesis of arginine and its significance in production of ruminant animals

Bahram Chacher — 2013-04-10T00:00:00Z

Arginine (ARG) exerts many beneficial effects on animal body and enhanced angiogenesis, lactogenesis, which finally leads to the improvement in nitrogen (N) metabolism, reproduction, lactation, immunity and growth. Unfortunately, unprotected ARG will be degraded in the rumen and its price is high, thus feeding rumen-protected ARG seems to be uneconomical. Alternatively, N-carbamoyl glutamate (NCG) is structural analogue of N-acetyl glutamate, cofactor of cabamoyl phosphate synthetase1, is lower in rumen degradation compared to ARG. Additionally, rumen epithelial and duodenal cells have potentially utilized the NCG for ureagenesis. Supplementation of NCG to high yielding dairy cows increased plasma concentration of ARG and nitric oxide, decreased the plasma ammonia N and improved lactation performance and N utilization. Supplementation of NCG enhanced pregnancy rates in rats, improved litter size and fetal survival rate, thereby improved the reproductive performance of sows. Oral NCG supplementation increases plasma ARG and somatotropin levels, and increased growth rate and muscle protein synthesis in nursing piglets. The NCG is potential a relatively cheaper source of feed additive to offer vital compensation over oral administration of ARG, resulting in improved ruminant animal health and production. In this article, we reviewed the mechanism of ARG biosynthesis by NCG and their significance in growth, reproduction, milk production and N utilization in ruminant animals.

Absolute copy number differences of Y chromosomal genes between crossbred (Bos taurus × Bos indicus) and Indicine bulls

Ayan Mukherjee — 2013-04-04T00:00:00Z

Background: The Y chromosome in mammal is paternally inherited and harbors genes related to male fertility and spermatogenesis. The unique intra-chromosomal recombination pattern of Y chromosome and morphological difference of this chromosome between Bos taurus and Bos indicus make it an ideal model for studying structural variation, especially in crossbred (Bos taurus x Bos indicus) bulls. Copy Number Variation (CNV) is a type of genomic structural variation that gives information complementary to SNP data. The purpose of this study was to find out copy number differences of four Y chromosomal spermatogenesis-related candidate genes in genomic DNA of crossbred and purebred Indicine bulls.Result: Four Y chromosomal candidate genes of spermatogenesis namely, sex determining gene on Y chromosome (SRY), DEAD box polypeptide 3-Y chromosome (DDX3Y), Ubiquitin specific peptidase 9, Y-linked (USP9Y), testis-specific protein on Y chromosome (TSPY) were evaluated. Absolute copy numbers of Y chromosomal genes were determined by standard curve-based quantitative real time PCR. Copy numbers of SRY and TSPY genes per unit amount of genomic DNA are higher in crossbred than Indicine bulls. However, no difference was observed in DDX3Y and USP9Y gene copy numbers between two groups. Conclusion: The present study demonstrates that the structural organization of Y chromosomes differs between crossbred and Indicine bulls which are reproductively healthy as observed from analysis of semen attributes. The absolute copy numbers of SRY and TSPY genes in unit mass of genomic DNA of crossbred bulls are significantly higher than Indicine bulls. No alteration in absolute copies of DDX3Y and USP9Y gene was found between the genome of crossbred and Indicine bulls. This study suggests that the DDX3Y and USP9Y are likely to be single copy genes in the genome of crossbred and Indicine bulls and variation in Y chromosome length between crossbred and Indicine bulls may be due to the copy number variation of SRY gene and TSPY array.

Effects of exogenous enzymes and dietary energy on performance and digestive physiology of broilers

Jialing Zou — 2013-04-04T00:00:00Z

The study was conducted to compare the effects of XG with AG and BM at different metabolizable energy diets on growth performance, digestive physiology and energy utilization of broilers fed with corn-SBM diet. A 2 × 4 factorial design was used with two basal diets (the positive control group, PC; negative control with ME reduction 100 kcal/kg, NC) and with or without the addition of three exogenous enzymes (0.02% BM; 0.01% AG; 0.05% XG) respectively. 1,200 one-day-old broilers were randomly allocated to 8 treatments with 10 pens of 15 broilers. There was no significant difference on BW, BWG, and FI at 0-21d, 21-42d or 0-42d for diet, enzymes or their interactions, but FI at 22-42d and 0-42d were tend to be decreased with the addition of enzymes. The F/G was significantly improved by the addition of enzymes especially in NC diet. The dietary AME and TME in PC or NC diet were significantly increased by XG or AG in NC diet. The villus length and V/C of ileum were significantly increased by the addition of BM or XG. XG improved the activities of trypsin, chymotrypsin and amylase, BM improved the activity of trypsin at 21d, and AG improved the activity of chymotrypsin at 21d. Comparing to PC diet, the addition of enzymes in PC or NC diet decreased feed cost per kg body weight gain especially in NC diet (except AG in PC diet) with the highest profits for XG in NC diet. In conclusion, supplementation of 0.02% BM or 0.01% AG or 0.05% XG could improve feed conversion of broilers in corn-soybean meal diet by improving energy utilization and digestive physiology, and also supplementation of 0.05% XG had a preferable efficacy in low energy diet.

Phosphorylation of histone H3 on Ser10 by auto-phosphorylated PAK1 is not essential for chromatin condensation and meiotic progression in porcine oocytes

Bing-Yuan Wang — 2013-03-22T00:00:00Z

Background: The p21-activated kinase 1 (PAK1) is essential for mitosis and plays an important role in the regulation of microtubule assembly during oocyte meiotic maturation in mice; however, little is known about its role in porcine oocytes.ResultTotal p21-activated kinase 1 (PAK1) and phosphorylated PAK1 at Thr423 (PAK1Thr423) were consistently expressed in porcine oocytes from the germinal vesicle (GV) to the second metaphase (MII) stages, but phosphorylation of histone H3 at Ser10 (H3Ser10) was only expressed after the GV stage. Immunofluorescence analysis revealed that PAK1Thr423 and H3Ser10 colocalized on chromosomes after the GV stage. Blocking of endogenous PAK1Thr423 by injecting a specific antibody decreased the phosphorylation level of H3Ser10; however, it had no impact on chromatin condensation, meiotic progression, cleavage rate of blastomeres or the rate of blastocyst formation. Conclusion: Phosphorylation of PAK1Thr423 is a spontaneous activation process and the activated PAK1Thr423 can promote the phosphorylation of H3Ser10; however, this pathway is not required for meiotic maturation of porcine oocytes or early embryonic development.

Efficient production of chimeric mice from embryonic stem cells injected into 4- to 8-cell and blastocyst embryos

Minhua Hu — 2013-03-21T00:00:00Z

Background: Production of chimeric mice is a useful tool for the elucidation of gene function. After successful isolation of embryonic stem (ES) cell lines, there are many methods for producing chimeras, including co-culture with the embryos, microinjection of the ES cells into pre-implantation embryos, and use of tetraploid embryos to generate the full ES-derived transgenic mice. Here, we aimed to generate the transgenic ES cell line, compare the production efficiency of chimeric mice and its proportion to yield the male chimeric mice by microinjected ES cells into 4- to 8-cell and blastocysts embryos with the application of Piezo-Micromanipulator (PMM), and trace the fate of the injected ES cells. Results: We successfully generated a transgenic ES cell line and proved that this cell line still maintained pluripotency. Although we achieved a satisfactory chimeric mice rate, there was no significant difference in the production of chimeric mice using the two different methods, but the proportion of the male chimeric mice in the 4- to 8-cell group was higher than in the blastocyst group. We also found that there was no tendency for ES cells to aggregate into the inner cell mass using in vitro culture of the chimeric embryos, indicating that they aggregated randomly. Conclusions: These results showed that the PMM method is a convenient way to generate chimeric mice and microinjection of ES cells into 4- to 8-cell embryos can increase the chance of yielding male chimeras compared to the blastocyst injection. These results provide useful data in transgenic research mediated by ES cells.

Annual acknowledgement of manuscript reviewers

Defa Li — 2013-03-19T00:00:00Z

Contributing reviewersThe editors of Journal of Animal Science and Biotechnology would like to thank all our reviewers who have contributed to the journal in Volume 1 (2012).

Strategies to improve fiber utilization in swine

Brian Kerr — 2013-03-15T00:00:00Z

Application of feed processing methods and use of exogenous feed additives in an effort to improve nutrient digestibility of plant-based feed ingredients for swine has been studied for decades. The following review will discuss several of these topics, including: fiber characterization, impact of dietary fiber on gastrointestinal physiology, energy, and nutrient digestibility, mechanical processing of feed on fiber and energy digestibility, and the use of exogenous enzymes in diets fed to growing pigs. Taken together, the diversity and concentration of chemical characteristics that exists among plant-based feed ingredients, as well as interactions among constituents within feed ingredients and diets, suggests that improvements in nutrient digestibility and pig performance from mechanical processing or adding exogenous enzymes to diets fed to swine depends on a better understanding of these characteristics, but also relating enzyme activity to targeted substrates. It may be that an enzyme must not only match a target substrate(s), but there may also need to be a ′cocktail′ of enzymes to effectively breakdown the complex matrixes of fibrous carbohydrates, such that the negative impact of these compounds on nutrient digestibility or voluntary feed intake are alleviated. With the inverse relationship between fiber content and energy digestibility being well described for several feed ingredients, it is only logical that development of processing techniques or enzymes that degrade fiber, and thereby improve energy digestibility or voluntary feed intake, will be both metabolically and economically beneficial to pork production.