Live yeast and yeast extracts with and without pharmacological levels of zinc on nursery pig growth performance and antimicrobial susceptibilities of fecal Escherichia coli

A total of 360 weanling barrows (Line 200 ×400, DNA, Columbus NE; initially 5.6 ± 0.03 kg) were used in a 42-d study to evaluate yeast-based pre- and probiotics (Phileo by Lesaffre, Milwaukee, WI) in diets with or without pharmacological levels of Zn on growth performance and antimicrobial resistance (AMR) patterns of fecal Escherichia coli. Pens were assigned to 1 of 4 dietary treatments with 5 pigs per pen and 18 pens per treatment. Dietary treatments were arranged in a 2 × 2 factorial with main effects of yeast-based pre- and probiotics (none vs. 0.10% ActiSaf Sc 47 HR+, 0.05% SafMannan, and 0.05% NucleoSaf from d 0 to 7, then concentrations were lowered by 50% from d 7 to 21) and pharmacological levels of Zn (110 vs. 3,000 mg/kg from d 0 to 7, and 2,000 mg/kg from d 7 to 21 with added Zn provided by ZnO). All pigs were fed a common diet from d 21 to 42 post-weaning. There were no yeast ×Zn interactions or effects from yeast additives observed on any response criteria. From d 0 to 21, and 0 to 42, pigs fed pharmacological levels of Zn had increased (P < 0.001) ADG and ADFI. Fecal samples were collected on d 4, 21, and 42 from the same three pigs per pen for fecal dry matter (DM) and AMR patterns of E. coli. On d 4, pigs fed pharmacological levels of Zn had greater fecal DM (P = 0.043); however, no differences were observed on d 21 or 42. E. coli was isolated from fecal samples and the microbroth dilution method was used to determine the minimal inhibitory concentrations (MIC) of E. coli isolates to 14 different antimicrobials. Isolates were categorized as either susceptible, intermediate, or resistant based on Clinical and Laboratory Standards Institute (CLSI) guidelines. The addition of pharmacological levels of Zn had a tendency (P = 0.051) to increase the MIC values of ciprofloxacin; however, these MIC values were still well under the CLSI classified resistant breakpoint for Ciprofloxacin. There was no evidence for differences (P > 0.10) for yeast additives or Zn for AMR of fecal E. coli isolates to any of the remaining antibiotics. In conclusion, pharmacological levels of Zn improved ADG, ADFI, and all isolates were classified as susceptible to ciprofloxacin although the MIC of fecal E. coli tended to be increased. Thus, the short-term use of pharmacological levels of Zn did not increase antimicrobial resistance. There was no response observed from live yeast and yeast extracts for any of the growth, fecal DM, or AMR of fecal E. coli criteria.

A live yeast supplementation to gestating ewes improves bioactive molecules composition in colostrum with no impact on its bacterial composition and beneficially affects immune status of the offspring

Colostrum quality is of paramount importance in the management of optimal ruminant growth and infectious disease prevention in early life. Live yeast supplementation effect during the last month of gestation was evaluated on ewes colostrum composition. Two groups of ewes (n=14) carrying twin lambs were constituted and twins were separated into groups (mothered or artificially-fed) 12h after birth. Nutrient, oligosaccharides (OS), IgG and lactoferrin concentrations were measured over 72h after lambing, and bacterial community was described in colostrum collected at parturition (T0). Immune passive transfer was evaluated through IgG measurement in lamb serum. In both groups, colostral nutrient, OS concentrations and IgG concentrations in colostrum and lamb serum decreased over time, (p < 0.01) except for lactose, which slightly increased (p < 0.001) and lactoferrin which remained stable. Bacterial population was stable over time with high relative abundances of Aerococcaceae, Corynebacteriaceae, Moraxellaceae and Staphylococcaceae in T0-colostrum. No effect of supplementation was observed in nutrient and lactoferrin concentrations. In supplemented ewes, colostral IgG level was higher at T0 and a higher level of serum IgG was observed in lambs born from supplemented mothers and artificially-fed, while no effect of supplementation was observed in the mothered lambs groups. Using a metabolomic approach, we showed that supplementation affected OS composition with significantly higher levels of colostral Neu-5Gc compounds up to 5h after birth. No effect of supplementation was observed on bacterial composition. Our data suggest that live yeast supplementation offsets the negative impact of early separation and incomplete colostrum feeding in neonate lambs.

Evolution of increased early-life fecundity but faster reproductive senescence in Drosophila melanogaster females through adaptation to chronic live-yeast deprivation

Dietary restriction is a common ecological challenge that limits reproduction. Yet only a few studies have explored adaptation under chronic protein deprivation. We subjected four replicate laboratory-adapted populations (YLB) of Drosophila melanogaster to a complete deprivation of live-yeast to mimic diet restricted ecology. In this insect, live-yeast is a critical source of protein that strongly affect reproductive output, especially in females. Following 24 generations of experimental evolution, compared to their matched controls (BL), females from YLB populations showed increase in reproductive output early in life, both in presence and absence of live-yeast. The observed increase in reproductive output was not associated with any accommodating alteration in average egg size; and development time, pre-adult survivorship, and body mass at eclosion of the progeny. Interestingly, adult lifespan was also found to be unaffected. However, YLB females were found to have a significantly faster rate of reproductive senescence albeit without any change in a measure of lifetime reproductive output. Taken together, adaptation to LYD ecology shows that reproductive output can evolve without affecting lifespan, suggesting that widely observed reproduction-survival trade-off is not universal. Populations can optimize fitness by fine tuning the scheduling of reproduction even when lifetime reproductive output is constrained.

PSX-B-4 Effect of live yeast on the ruminal fermentation characteristics of growing steers in heat-stress conditions

The objective of this trial was to determine the influence of live yeast supplementation (LY) and temperature exposure (TEMP) on the ruminal fermentation characteristics of steers receiving a grower diet. The effects of LY and TEMP were investigated using a 2 x 2 crossover design that spanned five periods. Eight Angus crossbred steers (365 ± 32 kg) were randomly split into pairs and housed in four outdoor pens outfitted with an individualized feeding system. Animals were limit fed a grower diet (DIET) at 1.2% SBW with no live yeast supplementation (NOY) or a grower diet top-dressed with 10 g live yeast/d for 14 days (1.2 × 1012 CFU/d). On days 13 and 14, animals were subjected to one of two TEMP conditions, thermoneutral (TN; 18.4 ± 1.1°C, 57.6 ± 2.8 % RH) or heat stress (HS; 33.8 ± 0.6°C, 55.7 ± 2.7 % RH), in two side-by-side, single-stall open-circuit, indirect respiration calorimetry chambers. Data were analyzed using a random coefficients model. Carryover effects were examined and removed from the model if not significant (P &gt; 0.05). There was no effect of DIET, TEMP, or DIET×TEMP (P &gt; 0.05) on ruminal pH, redox, ciliated protozoa count, acetate, butyrate, total VFA, and ruminal ammonia concentrations. Similarly, the acetate to propionate ratio was not influenced by DIET, TEMP, or DIET × TEMP (P ≥ 0.190). Propionate concentration was the greatest in animals in TN conditions receiving LY (P = 0.008). Compared to HS+NOY, HS+LY (P = 0.003) and TN+LY (P = 0.043) had greater ruminal enumerations of Fusobacterium necrophorum. This suggests LY (P = 0.010) provided a favorable environment for F. necrophorum during heat stress. Live yeast supplementation did not improve overall ruminal fermentation during heat stress. Additional research is required to better understand the dynamic relationship between live yeast and temperature exposure.

295 Effects of Live Yeast and Ruminal Environment on Beef Cattle Diet Digestibility: An in vitro Approach

The effects of live yeast (Saccharomyces cerevisiae) and ruminal environment on in vitro true digestibility of dry matter, organic matter, and fiber components were evaluated. Ruminally-cannulated beef steers (n = 4; BW = 520 ± 30 kg) were used in a cross-over design to serve as donors of ruminal content. In vitro substrates (6 grower and 6 finisher diets) and individual ingredients (steam-flaked corn, wet corn gluten feed, and old-world bluestem hay) were dehydrated (55o C), ground (1 mm), and incubated using a 2 × 2 factorial arrangement of treatments: a) the presence or not of yeast (8×109 CFU/animal-daily adjusted to a 70 L ruminal content volume), and b) two ruminal inoculums collected from donors fed a grower (50:50) or a finisher (92:08) diet (concentrate:forage). Four incubation batches (experimental unit) were performed, in which the initial two batches were performed followed by another two after animals switched diets and were adapted again during 21d. A Daisy in vitro incubation system was used, and samples incubated for 48h (39°C). The GLIMMIX procedure of SAS was used for the statistical analysis. No 3-way interactions (P ≥ 0.71) or 2-way interactions with substrate were observed (P ≥ 0.25). The in vitro true digestibility of DM, OM, NDF, and hemicellulose increased when yeast was added to the incubator containing a 50:50 ruminal content (Rumen × Yeast; P ≤ 0.02). The ADF digestibility increased (P = 0.02) with yeast addition regardless of ruminal content type (50:50 or 92:08). As expected, finisher substrate diets were more (P &lt; 0.01) digestible than grower diets. The combination of live yeast and a specific ruminal environment seemed to be more important than substrate type, in which live yeast improved in vitro digestion within a 50:50 ruminal inoculum more evidently.

220 Effects of Actisaf HR+ SC47 Live Yeast Probiotic Fed at Two Levels to Sows on Offspring Performance Before and After Weaning

750 sows (PIC line 42) were used to evaluate the effects of ActiSaf HR+ SC47 live yeast probiotic (AS) on sow and litter performance when fed to sows and their weaned piglets (PIC line 42 x 359). 250 multiparous sows per treatment (average parity 3.6) were fed the control diet without a live yeast probiotic (NC) or a diet with 250 mg/kg AS from breeding through lactation (LY1) or 250 mg/kg AS during gestation and 500 mg/kg AS during lactation. Weaned pigs from these sows were subsequently fed 4-phase nursery diets containing 0 (wNC) or 1 g/kg AS from d 0–10 after weaning followed by 500 mg/kg AS (wLY) from d 10–42 after weaning. This provided a 3x2 nursery trial design. During lactation, number of pigs born; born live varied by treatment (P &lt; 0.05). After weaning, wLY fed pigs had lower BW on d 12, 23; d 0–12 ADG, ADFI, lower d 0–42 ADFI and $/kg gained (P &lt; 0.05). Pigs fed wLY after weaning also tended towards lower d 42 BW and d 0–42 ADG (P &lt; 0.06; Table 1). Conversely, weaned pigs from sows fed LY1 or LY2 had higher ADG and ADFI from d 0–12 and d 0–42 after weaning (P &lt; 0.05) versus pigs from sows fed NC. Pigs from sows fed LY1 or LY2 also had higher BW at d 12, 23, and 42 after weaning than pigs from sows fed NC. Pigs from sows fed LY1 and LY2 tended to have lower nursery $/kg gain (P &lt; 0.06) than pigs from sows fed NC. No significant interactions were observed. Feeding ActiSaf HR+ SC47 live yeast probiotic to gestating and lactating sows improved their weaned pigs’ growth performance and tended to improve piglet cost of production after weaning.

PSXV-23 Effects of a nutritional packet composed of live yeast, vitamins, and electrolytes on the feeding behavior of intensively managed beef steers

The effect of a nutritional-packet was evaluated on time spent ruminating, eating, and chewing (ruminating + eating) by intensively managed beef steers consuming a finishing diet during the final 65 d of feeding prior to slaughter. Furthermore, the influence of behavior on CH4 production was determined. Twenty-four Angus-crossbreed steers were distributed into pens with SmartFeed (C-Lock) technology in which they were treated with: control or nutritional-packet [0.29% DM basis; live yeast (8.7 Log CFU/g); Vitamin C (5.4 g/kg); Vitamin B1 (13.33 g/kg); NaCl (80 g/kg); KCl (80 g/kg)]. An ear tag containing multiple accelerometers (CowManager) was placed on steers, and such device continuously recorded rumination and eating time (min/day). Enteric CH4 emissions were measured for 15 d using the SF6 tracer technique. Feeding behavior data were analyzed as a randomized complete block design using the MIXED procedure of SAS. The model included the fixed effect of treatment and the random effect of block. Steer was considered experimental unit. The GLM procedure of SAS was used for regressing behavior and CH4 production data. There were no differences between treatments for time (within 24 h) spent ruminating, eating, or chewing (P ³ 0.197). When nutrient intake was taken into account, no differences (P ³ 0.139) were observed between treatments for time spent ruminating, eating, and chewing per kg of dry matter, organic matter, neutral detergent fiber intake, and acid detergent fiber intakes. The production of CH4 was not affected by time spent ruminating (0.93 g/min; R2 = 0.0003; P = 0.935), eating (3.34 g/min; R2 = 0.03; P = 0.409), or chewing (0.69 g/min; R2 = 0.006; P = 0.728). The feeding behavior of intensively managed beef steers during the final 65-d of feeding was not driven by the nutritional-packet supplied, neither was CH4 production associated with feeding behavior variables measured.

First record of Spotted-wing drosophila Drosophila suzukii (Diptera: Drosophilidae) in Martín García Island wildlife refuge, Argentina

Here we report on the first peculiar detection of the spotted-winged drosophila, Drosophila suzukii (Matsumura) on Martín García Island, a wildlife refuge located in the Río de la Plata estuary, Argentina. Flies were collected using banana baited traps fermented with live yeast, in sandy areas with abundant presence of cactus in the interior of the island. The absence of cultivated host plants, e.g., fruit crops, and the small population of humans inhabiting the island make the presence of D. suzukii in this wildlife refuge unexpected. Previous detection of this fly in South America happened mostly within commercial fruit orchards and/or neighboring fields.