Use of faeces as an alternative inoculum to caecal content to study in vitro feed digestibility in domesticated ostriches (Struthio camelus var. domesticus)

In order to find an alternative source of inoculum to caecal content for studying the in vitro feed digestibility in domesticated ostriches (Struthio camelus var. domesticus), caecal content and faeces of 4 male birds were used as inocula for an in vitro gas production trial. 2. About 1 g of each of 5 substrates (maize silage, CS; alfalfa hay, AH; barley, BG; soybean meal, SM; beet pulp, BP) was weighed, in quadruplicate per inoculum, in 120 ml flasks; 75 ml of anaerobic medium and 4ml of reducing solution were added and flasks were kept at 39C. Caecal content and faeces were diluted respectively 1 : 2 (CI) and 1 : 4 (FI) with an anaerobic medium and were injected into the respective flasks (10 ml). 3. Gas production was recorded 22 times up to 120 h of incubation and fermentation characteristics (for instance, degraded organic matter, OMd; potential gas production, A; maximum fermentation rate, Rmax; time at which it is reached, Tmax; pH; volatile fatty acid, VFA; ammonia) were studied for each inoculum and substrate. 4. CI and FI showed significant differences in Tmax (1637 vs 1847 h, respectively), propionic (1647 vs 1207 mmoles/l) and butyric acid (650 vs 798 mmoles/l) and ammonia concentration (1718 vs 1995 mmoles/l). The substrates, according to their chemical composition, showed different fermentation characteristics. However, the regression equations able to estimate some fermentation characteristics of the caecum from those of faeces were statistically significant and showed R2-values ranging from 087 to 099. 5. The differences in fermentation pathways of the two inocula did not appear to influence the rate and extent of OM digestion. Faecal fermentation predicted rates and extent of OM digestion by caecal fermentation in ostriches; consequently, the faeces could be considered as an alternative to caecal content to study feed digestibility in the species, although there is a need to undertake further research. INTRODUCTION To obtain a useful feed value, it is necessary to determine digestibility specifically for ostriches, where the nutritive value of feeds used for diet formulation is very often erroneously determined using poultry. The ostrich caecum provides a suitable environment for the fermentation of dietary fibre. Feed digestibility of ostriches in vivo has been determine

Regulation of Stearoyl Coenzyme A Desaturase 1 Gene Promoter in Bovine Mammary Cells

Stearoyl-Coenzyme A desaturase 1 (SCD1) belongs to the fatty acid family of desaturases. In lactating ruminants, the SCD1 protein is highly expressed in the mammary gland and is relevant for the fatty acid composition of milk and dairy products. Bovine mammary epithelial cells (BME-UV1), cultured in vitro, have been proposed as a model to reproduce the biology of the mammary gland. The present study was designed to investigate the responsiveness of bovine SCD1 promoter to serum, insulin, oleic acid, and NFY transcription factor in BME-UV1 cells. A luciferase-based reporter assay was used to monitor the transcriptional activity of the SCD1 promoter region in BME-UV1 cells treated or not with insulin and/or oleic acid. The level of endogenous SCD1 mRNA was evaluated by Real time PCR. Insulin (20 ng/mL) induced a 2.0 to 2.5-fold increase of SCD1 promoter activity. Additionally, the effect of insulin was inhibited by oleic acid, serum components, and NFY enforced expression. Serum and NFY showed no synergistic or additive effect on SCD1 promoter activity suggesting that they repress SCD1 transcription through the same responsive element

In vitro fermentation characteristics of diets with different forage/concentrate ratios: comparison of rumen and faecal inocula

BACKGROUND: The aim of this trial was to evaluate the replacement of rumen fluid with faeces as inoculum in studying the invitrofermentationcharacteristicsofdietsforruminantsusingtheinvitrogasproduction technique.Sixiso-proteindietswith different forage/concentrate ratios were incubated with rumen fluid (RI) or faeces (FI) collected from sheep. RESULTS: Most of the fermentation parameters were influenced by diet and inoculum (P < 0.01). With both inocula, organic matterdegradability(dOM),cumulativegasproduction(OMCV)andmaximumfermentationrate(Rmax)increasedastheamount ofconcentrateinthedietincreased.Rmax waslowerwithFIvsRI(P < 0.01);dOMwashigherwithFIvsRIandthediet×inoculum interaction was significant. As expected, with both inocula, Rmax increased as the neutral detergent fibre content of the diet decreased. Significant correlations were obtained using both inocula between OMCV/dOM and gas/volatile fatty acid (VFA), while the correlation VFA/dOM was significant only with FI. The microbial biomass yield calculated by stoichiometric analysis for all diets was higher with FI vs RI. With FI the organic matter used for microbial growth showed an overall decreasing trend as the amount of concentrate in the diet increased. CONCLUSION: The results indicate that both faeces and rumen fluid from sheep have the potential to be used as inoculum for the in vitro gas production technique