Designing and evaluation of urea microcapsules in vitro to improve nitrogen slow release availability in rumen.

BACKGROUND: There is a growing interest in the development of novel and innovative vehicles for controlled release of urea into the rumen, aiming to provide ammonia-N for the biosynthesis of proteins of bacterial origin and to prevent urea intoxication by direct feeding to livestock. Urea microencapsulation is a system that can control the release of urea to be slow and steady. RESULTS: The amount of encapsulated urea was 69% of CSU (calcium silicate + urea + Eudragit RS100® + dichloromethane) and 71% of ACU (activated charcoal + urea + Eudragit RS100® + dichloromethane) groups (p > 0.05) The buoyancy of the microcapsules was over 50% after 12 h of agitation in both groups (CSU and ACU), producing significant differences in the volume of the organic phase factor, which was 20 mL at the lowest value (p = 0.0005). The morphology of the microcapsules produced with CSU and ACU showed no significant differences in microcapsule morphology (p > 0.05). The lower temperature (35 versus 40 °C, p = 0.035) retained better morphology of the microcapsules. Regarding the in vitro ammonia-N release kinetics, unprotected urea reached a maximal peak after 6 h, while CSU and ACU took more than 24 h to reach ammonia-N released concentration. CONCLUSIONS: We stabilized the physical factors in the microencapsulation of urea that can allow slow release of rumen fluid. © 2018 Society of Chemical Industry.

Effect of increasing levels of seven tree species extracts added to a high concentrate diet on in vitro rumen gas output.

This study was conducted to investigate the effects of increasing levels of extracts of Byrsonima crassifolia, Celtis pallida, Enterolobium cyclocarpum, Fraxinus excelsior, Ficus trigonata, Phoradendrom brevifolium and Prunus domestica on in vitro gas production (GP) and ruminal fermentation of a high concentrate diet. Plant extracts were prepared at 1 g dry matter (DM)/8 mL of solvent mixture (methanol : ethanol : water, 1:1:8) and added at levels of 0, 0.6, 1.2 and 1.8 mL/g DM of a high concentrate diet. In vitro GP was recorded at 2, 4, 6, 8, 10, 12, 24, 48 and 72 h of incubation. Increasing addition of extracts linearly increased (P < 0.001), the GP24 , GP48 and GP72 (mL/g DM), and linearly decreased (P < 0.001), the discrete GP lag time. Moreover, increasing extract doses linearly increased (P < 0.001) the asymptotic GP and decreased (P < 0.001) the rate of GP. GP6 was not impacted by treatments and GP12 increased linearly (P = 0.01) with increasing addition of extracts. Rumen pH declined linearly (P < 0.05) with increasing doses of extracts added. As no interactions (P > 0.05) occurred between the extracts and doses, it could be conclude that all extracts positively modified rumen fermentation at doses of 1.2 to 1.8 mL extract/g diet DM.

Effect of field pea (Pisum sativum L.) level on intake, digestion, ruminal fermentation and in vitro gas production in sheep fed maintenance diets.

The objective of this study was the characterization of the nutritive value, ruminal fermentation and nutrient digestibility of field pea (Pisum sativum L.) hay (FPH) by-product through in situ, in vitro and in vivo tests. A FPH diet was administered ad libitum to four sheep (live weight (LW) 38.0 ± 2.0 kg) at four inclusion levels (0, 25, 50 and 75%) over a conventional sorghum grain/oat straw ration in a 4 × 4 Latin square design. The in situ degradability of FPH was 67% dry matter (DM), 71% crude protein and 66% neutral detergent fiber (NDF). The inclusion of FPH did not affect (P ≥ 0.05) the DM (61 ± 0.4 g/LW(0.75) /day) and organic matter (OM) intake (56 ± 0.7 g/LW(0.75) /day). Total DM digestibility (68 ± 2.5%), OM (70 ± 3%), and NDF (60 ± 3%), were not different (P ≥ 0.05) between control and FPH inclusion diets. The diet had no effect on ruminal pH, ruminal ammonia concentration, total and individual volatile fatty acids. The chemical composition and sheep intake behavior indicate that FPH by-product is medium quality forage when incorporated in maintenance rations.

Viability tests, active caspase-3 and -7, and chromatin structure in ram sperm selected using the swim-up procedure.

Swim-up (SU) is a technique that permits the obtaining of motile sperm. Based on the sperm motility of neat ejaculates, we analyzed functional parameters, cytoplasmic esterases, and mitochondrial dehydrogenases of ram sperm using calcein acetomethylester and resazurin, respectively. Active caspase-3 and -7 and chromatin structure were evaluated in ram sperm before and after the SU process. There were no changes in any of the viability parameters after SU in neat semen samples with less or more than 25% motility. The percentage of active caspase-3 and -7 decreased after SU (68.8 +/- 4.6 vs 54.2 +/- 6.0), whereas a small but significant increase of chromatin structural abnormalities was observed (DNA fragmentation index [DFI], 287.3 +/- 3.1 vs 297.2 +/- 2.4). For the first time, the location of active caspase-3 and -7 was described for ram sperm. Notably, we found active caspases in the implantation fossa region. The presence of active caspases in neat ejaculates and the diminished presence of active caspases in SU-processed ejaculates suggest a role for caspases in motility and possibly in male fertility. The results of this study indicate that the evaluation of more than one cell-function marker is necessary to appropriately evaluate sperm quality. Furthermore, in semen samples with low motility, a lower percentage of sperm with active caspases is obtained after SU, although these sperm present increased values of DFI.