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Porcine deltacoronavirus (PDCoV) was identified in multiple states across the United States (US) in 2014. In this study, we investigate the presence of PDCoV in diagnostic samples, which were further categorized by case identification (ID), and the association between occurrence, age, specimen and location between March and September 2014. Approximately, 7% of the case IDs submitted from the US were positive for PDCoV. Specimens were categorized into eight groups, and the univariate analysis indicated that oral fluids had 1.89 times higher odds of detecting PDCoV compared to feces. While the 43-56 day age group had the highest percentage of PDCoV positives (8.4%), the univariate analysis indicated no significant differences between age groups. However, multivariable analysis for age adjusted by specimen indicated the >147 day age group had 59% lower odds than suckling pigs of being positive for PDCoV. The percentage of PDCoV in diagnostic samples decreased to <1% in September 2014. In addition, 19 complete PDCoV genomes were sequenced, and Bayesian analysis was conducted to estimate the emergence of the US clade. The evolutionary rate of the PDCoV genome is estimated to be 3.8×10(-4) substitutions/site/year (2.3×10(-4)-5.4×10(-4), 95% HPD). Our results indicate that oral fluids continue to be a valuable specimen to monitor swineherd health, and PDCoV has been circulating in the US prior to 2014.

Rotaviruses (RVs) are a major etiological agent of acute viral gastroenteritis in humans and young animals, with rotavirus B (RVB) often detected in suckling and weaned pigs. Group A rotavirus classification is currently based on the two outer capsid proteins, VP7 and VP4, and the middle layer protein, VP6. Using RVB strains generated in this study and reference sequences from GenBank, pairwise identity frequency graphs and phylogenetic trees were constructed for the eleven gene segments of RVB to estimate the nucleotide identity cutoff values for different genotypes and determine the genotype diversity per gene segment. Phylogenetic analysis of VP7, VP4, VP6, VP1–VP3, and NSP1–NSP5 identified 26G, 5P, 13I, 5R, 5C, 5M, 8A, 10N, 6T, 4E, and 7H genotypes, respectively. The analysis supports the previously proposed cutoff values for the VP7, VP6, NSP1, and NSP3 gene segments (80%, 81%, 76% and 78%, respectively) and suggests new cutoff values for the VP4, VP1, VP2, VP3, NSP2, NSP4, and NSP5 (80%, 78%, 79%, 77% 83%, 76%, and 79%, respectively). Reassortment events were detected between the porcine RVB strains from our study. This research describes the genome constellations for the complete genome of Group B rotaviruses in different host species.

Rotaviruses (RV) are important causes of diarrhea in animals, especially in domestic animals. Of the 9 RV species, rotavirus A, B, and C (RVA, RVB, and RVC, respectively) had been established as important causes of diarrhea in pigs. The Minnesota Veterinary Diagnostic Laboratory receives swine stool samples from North America to determine the etiologic agents of disease. Between November 2009 and October 2011, 7,508 samples from pigs with diarrhea were submitted to determine if enteric pathogens, including RV, were present in the samples. All samples were tested for RVA, RVB, and RVC by real time RT-PCR. The majority of the samples (82%) were positive for RVA, RVB, and/or RVC. To better understand the risk factors associated with RV infections in swine diagnostic samples, three-level mixed-effects logistic regression models (3L-MLMs) were used to estimate associations among RV species, age, and geographical variability within the major swine production regions in North America. The conditional odds ratios (cORs) for RVA and RVB detection were lower for 1–3 day old pigs when compared to any other age group. However, the cOR of RVC detection in 1–3 day old pigs was significantly higher (p < 0.001) than pigs in the 4–20 days old and >55 day old age groups. Furthermore, pigs in the 21–55 day old age group had statistically higher cORs of RV co-detection compared to 1–3 day old pigs (p < 0.001). The 3L-MLMs indicated that RV status was more similar within states than among states or within each region. Our results indicated that 3L-MLMs are a powerful and adaptable tool to handle and analyze large-hierarchical datasets. In addition, our results indicated that, overall, swine RV epidemiology is complex, and RV species are associated with different age groups and vary by regions in North America.

No abstract

Corn and cassava are readily available and are the most popular starch sources in Thailand and other Southeast Asian countries. However, the cost of these starch sources has risen due to increasing interest in their use for animal feed, especially in ruminant livestock. Indeed, corn and cassava as ruminant feed ingredients have become highly competitive (Wanapat et al., 2012). On the other hand, byproducts of agricultural and pharmaceutical industries have replaced some corn and cassava recently. One such byproduct is pineapple stem starch (PS), the residue from the extraction of bromelain enzyme, which is mainly intended for pharmaceutical use. PS is high in starch content, in particular, amylose, compared with corn and cassava (Nakthong et al., 2017). The availability of PS in terms of amount and price may allow this material to be applied to animal feed as an alternative cost effective energy source to corn and cassava. However, no detailed evaluation in relation to demand and impact on the feed market has been made for potential application of PS to ruminant livestock, in particular, fattening cattle, the main target of such new starch sources. Ruminal hydrolysis of a starchy diet is not simply a process by which ⍺−1, 4 and 1, 6 linkages are cleaved by amylase enzymes, as other factors besides starch breakdown exist. In fact, among the many starch sources available as a concentrate ingredient, considerable variations exist in chemical and physical characteristics including proportions of amylose and amylopectin, starch-associated lipids and proteins, and size of starch granules (Stevnebo et al., 2009; Svihus et al., 2005), all of which affect the rate and extent of starch hydrolysis and fermentation in the rumen. Therefore, all of these factors need to be considered, especially when a new starch source is evaluated. One of the most important measures in the evaluation of starch sources is the response of rumen microbes and associated

No abstract

The effects of PS were determined as a concentrate added to feed and of the days it was short-term and long-term fed to fattening dairy steers on their growth performance, carcass characteristics, meat quality, and economic return. The experimental units comprised 36 feedlot dairy steers arranged as a 2 ⋅ 3 factorial in a completely randomized design. The first term (diet factors) consisted of ground corn (GC), ground cassava (CA), or pineapple stem starch (PS) at 37% dry matter (DM) in the concentrate. The second term (feeding factors) consisted of feeding the concentrate from 1 to 206 days (short-term feeding) or from 1 to 344 days (long-term feeding). At the end of the feeding term periods, the animals were slaughtered and the growth performance, carcass characteristics, and meat quality were evaluated. The average daily gain (ADG), feed:gain ratio, dry matter intake (DMI), hot carcass and cool carcass percentages, and backfat thickness were greater for steers on short-term than on long-term feeding. Feeding the different starch sources had no negative influence on the growth performance, carcass characteristics, and meat quality. However, the ADG of steers fed PS tended (P = 0.07) to be higher than for those fed GC or CA. In addition, the concentration of the fatty acid C14:1 in the longissimus dorsi muscle was the highest in steers fed CA. Different starch sources had similar values for saturated fatty acid (SFA) and monounsaturated fatty acid (MUFA.) Long-term feeding increased MUFA. Pineapple stem starch could be a useful feed ingredient for feedlot steers as an alternative starch source for energy.