Dose-response effects of in-feed antibiotics on growth performance and nutrient utilization in weaned pigs fed diets supplemented with yeast-based nucleotides

Dietary nucleotides are bioactive compounds with the potential to mitigate weaning-associated challenges in piglets. An experiment was conducted to determine the interaction effect of antimicrobial growth promoters (AGP) and a nucleotide-rich yeast extract (NRYE) on growth performance and apparent total tract digestibility (ATTD) of dry matter (DM), crude protein (CP) and gross energy (GE), and to establish whether NRYE supplementation may completely or partially replace AGP in diets for weaned pigs. In phase 1 and 2, corn, wheat, canola meal and soybean meal based diets, which were formulated to contain 0.0 or 0.1% NRYE with 0, 25, 50, 75 or 100% of the recommended AGP dosage, were fed to 108 twenty-one day old piglets (initial body weight 7.11 ± 0.9 kg; mean ± SD) from d 1 to 14 and 15 to 28, respectively. Overall, increasing AGP level in NRYE supplemented diets linearly decreased average daily gain (ADG) (P = 0.002) and gain-to-feed ratio (G:F) (P = 0.007); and quadratically decreased ATTD of DM (P = 0.001), CP (P = 0.003) and G:F (P = 0.017) during phase 2. Compared with control and pigs fed NRYE with 100% of recommended AGP dosage, pigs fed 0.1% NRYE without AGP had greater (P < 0.05) ADG and G:F in phase 2 and overall. In conclusion, supplementing 0.1% NRYE improved growth performance of pigs but this beneficial effect was reduced by increasing dietary AGP dosage. Keywords: Antimicrobial growth promoters, Digestibility, Growth performance, Piglet, Nucleotide-rich yeast extrac

Short-term effect of supplemental yeast extract without or with feed enzymes on growth performance, immune status and gut structure of weaned pigs challenged with Escherichia coli lipopolysaccharide

Abstract Background This study investigated the response of piglets receiving a yeast extract without or with a multi-enzyme mixture compared with an antimicrobial growth promoter (AGP) on performance, immune status and gut structure after an E. coli lipopolysaccharide (LPS) challenge. Thirty-six pigs were allotted to six treatments including: a non-challenged control (NCC); LPS-challenged control (CC); CC + AGP; CC + yeast extract; CC + enzymes; and CC + enzymes + yeast extract. On d 7, pigs were bled and thereafter injected with LPS or sterile saline. Blood samples were collected at 6, 48, and 96 h post-challenge. After 96 h post-challenge, pigs were euthanized to obtain duodenal, jejunal and ileal samples. Results Overall (d 1 to 11), compared with CC pigs, AGP attenuated the LPS-induced reduction in ADG (P = 0.004), ADFI (P = 0.03) and gain/feed ratio (P = 0.01). At 6 h post-challenge, AGP pigs had lower plasma urea N (PUN; P = 0.02) and serum TNF- α concentration (P = 0.07), and higher platelet count (P = 0.04) and serum IL-10 concentration (P = 0.02) than CC pigs. At 48 h post-challenge, AGP pigs had lower PUN (P = 0.02) than CC pigs, whereas enzymes + yeast extract interacted non-additively (P = 0.001) to reduce PUN. At 96 h post-challenge, AGP pigs had lower PUN (P = 0.02) and higher duodenal (P = 0.03), jejunal (P = 0.01) and ileal (P = 0.07) villus height than CC pigs. In addition, enzymes + yeast extract interacted additively and non-additively to reduce ileal IFN-γ (P  0.10) were observed between AGP and enzymes + yeast extract pigs on other measured parameters except for the downregulation of ileal IFN-γ (P < 0.0001) and TNF-α (P = 0.003) in enzymes + yeast extract pigs at 96 h post-challenge. Conclusions The LPS challenged piglets receiving enzymes + yeast extract showed beneficial responses in gut structure and immunity commensurate with those receiving antibiotics, though the latter had better overall growth performance

Dietary Inclusion of a Mixed Powder of Medicinal Plant Leaves Enhances the Feed Efficiency and Immune Function in Broiler Chickens

The trial was designed to determine the effect of the mixed powder of leaves of Anacardium occidentale (60%), Psidium guajava (20%), and Morinda citrifolia (20%) on growth performance, nutrient digestibility, and immunoglobulin concentration in broiler chickens. A total of 80 one-day-old Ross 308 broiler chickens were randomly assigned to two dietary treatments from days 1 to 21 of age, with 8 replicates by treatments and 5 birds per replicate. Treatments consisted of a control diet (T0) and the dietary inclusion of 0.5% of mixed powder of medicinal plant leaves (T1). The inclusion of herbs decreases the feed intake (FI) and feed conversion ratio (FCR; P0.05) on nutrient digestibility and IgA concentration; however, the IgG concentration increased by the effect of this experimental treatment. The results allow recommending the dietary inclusion of mixed powder of medicinal plant leaves as an alternative for obtaining acceptable performance in broilers

Modeling the Incidence of Maize Spotted Stem-Borer (Chilo partellus) Infestation Under Long-Term Organic and Conventional Farming Systems

The damage levels of the maize spotted stem borers (Chilo partellus Swinhoe) are estimated at 400,000 metric tons, which is equivalent to 13.5% of farmers' annual maize harvest accounting for US$80 million. Despite the economic importance of the pest, information on the incidence under long-term organic and conventional farming systems is lacking. This study evaluated three different link functions [logit, probit, and complementary log-log – (clog-log)] to reduce prediction errors in overdispersed stem borer incidence data for 12 years in four farming systems. The clog-log link function had the lowest Akaike information criterion (AIC) and Bayesian information criterion (BIC) indexes for the pest incidence model in Thika. Contrarily, probit showed the lowest AIC and BIC in the Chuka incidence data model. The residual diagnostic plots with clog-log demonstrated no patterns against the predicted values. Our findings revealed that clog-log link function provided the best fit in beta-binomial mixed models compared to others. We advocate for the use of clog-log for long-term pest incidence data modelling to obtain biologically realistic projections. Users of mixed models must incorporate explicit consideration of suitable link function discrimination, model fit and model complexity into their decision-making processes if they build biologically realistic models