Influence of a whole yeast product (Pichia guilliermondii) fed throughout gestation and lactation on performance and immune parameters of the sow and litter.

A study was conducted using 3 groups of gestating gilts and sows (n = 98) to determine the effects of Pichia guilliermondii (Pg), a whole cell-inactivated yeast product (CitriStim; ADM Alliance Nutrition), on performance and immune parameters of dams and litters. Within 24 h of breeding, gilts and sows were allotted to 1 of 3 treatments consisting of a control (SC) diet or SC diet supplemented with 0.1 (S1) or 0.2% (S2) Pg. Dietary treatments were maintained through lactation. Colostrum and milk (day 14) samples were collected for IgA, IgG, and IgM analysis. Blood samples were collected from sows on day 110 of gestation (group 3 only), while at weaning for all 3 groups, and from piglets at 14 d of age for peripheral white blood cell counts and serum IgA, IgG, and IgM analysis. Inclusion of Pg resulted in an increase in number born alive as the level of Pg increased (12.49, 13.33, and 13.43 born alive per litter for SC, S1, and S2, respectively; linear effect [LS], P = 0.003). Additionally, the percentage of piglets weighing less than 0.9 kg at birth was reduced in sows provided Pg at 0.1% or 0.2% compared with control (LS, P = 0.006). Sows receiving Pg during gestation and lactation also weaned a greater number of piglets (10.31, 10.55, and 10.60 weaned per litter in control, 0.1% and 0.2% Pg, respectively; LS, P = 0.02). However, percent preweaning mortality was 17.58%, 19.38%, and 19.61% for control, 0.1%, and 0.2% Pg, respectively (LS, P = 0.02). There were no differences in gestation BW gain, farrowing (days 110 to 48 h postfarrowing) or lactation (day 110 to weaning) BW loss, number of mummies or stillborn, or piglets' individual birth or weaning weight. On day 110 of gestation, the neutrophil concentration (quadratic effect [QS], P = 0.03) and neutrophil:lymphocyte ratio (QS, P = 0.04) in peripheral blood were greater in S1 than SC, with S2 being intermediate. At weaning there was a linear increase in neutrophil concentration (P = 0.03), neutrophil:lymphocyte ratio (P = 0.01), and percentage of neutrophils in the leukocyte population (P = 0.01) as level of Pg increased in sow diets. In conclusion, Pg inclusion in sow diets linearly increased total number born alive and weaned, with no change in average birth or weaning weight, and decreased the number of lightweight pigs at birth. However, inclusion of Pg had no effect on immune parameters measured in milk, colostrum, or day 14 piglet serum, but increased the peripheral blood neutrophil concentration of gilts and sows.

Pipeline for amplifying and analyzing amplicons of the V1-V3 region of the 16S rRNA gene.

BACKGROUND: Profiling of 16S rRNA gene sequences is an important tool for testing hypotheses in complex microbial communities, and analysis methods must be updated and validated as sequencing technologies advance. In host-associated bacterial communities, the V1-V3 region of the 16S rRNA gene is a valuable region to profile because it provides a useful level of taxonomic resolution; however, use of Illumina MiSeq data for experiments targeting this region needs validation. RESULTS: Using a MiSeq machine and the version 3 (300 × 2) chemistry, we sequenced the V1-V3 region of the 16S rRNA gene within a mock community. Nineteen bacteria and one archaeon comprised the mock community, and 12 replicate amplifications of the community were performed and sequenced. Sequencing the large fragment (490 bp) that encompasses V1-V3 yielded a higher error rate (3.6 %) than has been reported when using smaller fragment sizes. This higher error rate was due to a large number of sequences that occurred only one or two times among all mock community samples. Removing sequences that occurred one time among all samples (singletons) reduced the error rate to 1.4 %. Diversity estimates of the mock community containing all sequences were inflated, whereas estimates following singleton removal more closely reflected the actual mock community membership. A higher percentage of the sequences could be taxonomically assigned after singleton and doubleton sequences were removed, and the assignments reflected the membership of the input DNA. CONCLUSIONS: Sequencing the V1-V3 region of the 16S rRNA gene on the MiSeq platform may require additional sequence curation in silico, and improved error rates and diversity estimates show that removing low-frequency sequences is reasonable. When datasets have a high number of singletons, these singletons can be removed from the analysis without losing statistical power while reducing error and improving microbiota assessment.