Effects of different doses of Salix babylonica extract on growth performance and diet in vitro gas production in Pelibuey growing lambs

Pelibuey sheep is the main breed in the tropical and subtropical regions of Mexico, and high demand of sheep meat has favored the finishing of lambs in feedlots with diets containing high levels of grains. The objective of this study was to evaluate the effects of exogenous enzymes (EE) and application method on nutrient intake and digestibility and performance of growing Pelibuey lambs. Treatments were based on comparison of two different methods of adding an enzyme product (sprayed on the total mixed ration or applied orally to the lambs) versus control treatment (no added enzyme). Twenty-one Pelibuey lambs, weighing 15.7 kg (SD = 1.8 kg) initial body weight, were individually housed in shaded pens and assigned randomly to one of the three enzyme treatments. At the end of study (lasting for 45 days), three lambs from each treatment were randomly selected and adapted to a pants and harness designed for fecal collection to measure nutrient digestibilities. Total body gain and average daily gain were affected (P < 0.05) by supplemental EE. The application method of EE had significant (P < 0.05) effect on FCE and FCR, but no effects were observed on nutrient intake. Supplemental EE did improve (P < 0.05) the digestibilities of dry matter, organic matter, neutral and acid detergent fiber, but no differences were observed in crude protein digestibility. The application method of EE had significant (P < 0.05) effect on the digestibility of acid detergent fiber. Supplemental EE can improve body weight gain and nutrient digestibilities without affecting nutrient intake in Pelibuey lambs, but the results of feed conversion efficiency and acid detergent fiber digestibility depend on the application method used of the EE.

The aim of the present study was to evaluate the effects of marine microalgae (Dunaliella salina) as a food additive on biogas (BG), methane (CH₄), carbon monoxide (CO), and hydrogen sulfide (H₂S) production kinetics, as well as in in vitro rumen fermentation and the CH₄ conversion efficiency of different genotypes of maize (Zea mays L.) and states of forage. The treatments were characterized by the forage of five maize genotypes (Amarillo, Montesa, Olotillo, Tampiqueño, and Tuxpeño), two states of forage (fresh and ensiled), and the addition of 3% (on DM basis) of microalgae (with and without). The parameters (b = asymptotic production, c = production rate, and Lag = delay phase before gas production) of the production of BG, CH₄, CO, and H₂S showed an effect (p < 0.05) of the genotype, the state of the forage, the addition of the microalgae, or some of its interactions, except for the time in the CO delay phase (p > 0.05). Moreover, the addition of microalgae decreased (p < 0.05) the production of BG, CH₄, and H₂S in most of the genotypes and stages of the forage, but the production of CO increased (p < 0.05). In the case of fermentation characteristics, the microalgae increased (p < 0.05) the pH, DMD, SCFA, and ME in most genotypes and forage states. With the addition of the microalgae, the fresh forage from Olotillo obtained the highest pH (p < 0.05), and the ensiled from Amarillo, the highest (p < 0.05) DMD, SCFA, and ME. However, the ensiled forage produced more (p < 0.05) CH₄ per unit of SFCA, ME, and OM, and the microalgae increased it (p < 0.05) even more, and the fresh forage from Amarillo presented the highest (p < 0.05) quantity of CH₄ per unit of product. In conclusion, the D. salina microalga showed a potential to reduce the production of BG, CH₄, and H₂S in maize forage, but its effect depended on the chemical composition of the genotype and the state of the forage. Despite the above, the energy value of the forage (fresh and ensiled) improved, the DMD increased, and in some cases, SCFA and ME also increased, all without compromising CH₄ conversion efficiency.

Goat milk composition is affected by feeding, and in semiarid rangeland, information on Creole goat milk physicochemical composition is lacking. For the fulfillment of this objective, three agroecological regions (AR) considering altitude (lowland 87, highland 779, and mountain 1309 m above sea level) with different botanical compositions were chosen. Every AR analyzed accounted for 30 goat herds, with a total of 90 herds. The results demonstrated that altitude had an influence mainly on density and protein. Milk density increases as altitude increases; conversely, milk protein increases as altitude decreases. On the other hand, in the mountain and lowland ARs, the salts and solids not fat (SNF) percentages were higher compared to that of the highland AR (p < 0.05). The freezing point (FP) was higher at highland altitudes compared to that of mountain and lowland ARs (p < 0.01). In the milk fatty acids (FA) profile, only the C14:1 value was affected by altitude, whereas goat milk at lowland and mountain altitudes had higher values compared to that at highland altitudes (p < 0.05). Additionally, late lactation stage fat, FP, and pH values were higher compared to early lactation values. The opposite effect was observed for salts and SNF. In the FA profile, late lactation values were higher for C10:0 and C8:0 compared to early lactation values. The opposite trend was observed for C18:2n6t. The thrombogenic index was significantly higher at lowland altitudes compared to highland altitudes, and similar to the mountain AR. These goat milk characteristics could be explained as a consequence of animal nutrition, as well as the goat’s meat-type phenotype.

The objective of this study was to evaluate the effects of three fibrolytic enzyme products (cellulase (CEL), xylanase (XYL) and a 1:1 mixture of CEL and XYL (MIX)) at three dose levels (0, 1 and 3 μL/0.5 g DM) on the in vitro fermentation of a diet for growing lambs. Bottles were incubated for 96 h at 39 °C. A mathematical model was used to estimate the parameters describing the gas production (GP) curve (b, c and L). Dry matter degradability (DMD) and fibre (NDFD and ADFD) degradability were determined at the end of the incubation period. Metabolisable energy (ME) and short chain fatty acids (SCFA) were calculated at 24 h of incubation. The asymptotic GP (parameter b) was affected (p < 0.02) by enzyme product and dose level, with a significant linear response (p < 0.05). Dose level affected ME and SCFA with a significant linear (p < 0.05) and quadratic (p < 0.01) response. The interaction between enzyme product and dose level was significant (p < 0.05) for cumulative GP up to 72 and 96 h of incubation, pH, ADFD and DMD. The results suggest that application of exogenous cellulases has the potential to alter asymptotic GP and degradability of ADF and DM of a diet for growing lambs, but most of the results depend on the interaction between enzyme product and dose level. Future studies are required to determine the ideal combination between enzyme product and dose level for optimal degradation of ruminant feeds.

The objective of this study was to evaluate the impact of the genotype on the chemical composition, feeding value and in vitro rumen degradability of fresh and ensiled forage of four native maize varieties (Amarillo, Olotillo, Tampiqueño and Tuxpeño) from Tamaulipas, Mexico, and a commercial hybrid, as well as the stability and aerobic deterioration of the silage. In all genotypes, fresh forage consisted of whole plants of maize that were harvested when the grain reached a milky-mass state, and silage was fresh forage chopped and ensiled in plastic bags, where it fermented for 120 days. The hybrid presented the highest content (p < 0.05) of dry matter (DM), organic matter (OM), ether extract, non-fibrous carbohydrates (NFCs) and starch, as well as the lowest content (p < 0.05) of fibers (NDF and ADF), acid detergent lignin and water-soluble carbohydrates (WSCs). Furthermore, the hybrid and Amarillo genotypes obtained the lowest pH and ammoniacal nitrogen content (p < 0.05), intermediate values (p < 0.05) of lactic and butyric acid, and the lowest and highest acetic acid content (p < 0.05), respectively. Although OM did not differ (p > 0.05) between states of the forage, the fresh forage presented a higher (p < 0.05) content of DM, crude protein, NDF, ADF, WSCs, pH and butyric acid in all genotypes, while the rest of the parameters were higher (p < 0.05) in the silage. However, Amarillo obtained the highest feeding value (p < 0.05) in terms of DM intake, relative forage value, digestible energy, metabolizable energy and rumen degradability (DM, NDF and ADF), and between states of the forage, ensiled obtained the highest feeding value (p < 0.05). During the aerobic exposure, the Amarillo and hybrid silage showed greater (p < 0.05) stability (>38 h), and less (p < 0.05) deterioration, pH increase and loss of DM and OM, while Tuxpeño obtained less stability and greater deterioration. In conclusion, the genotype did influence the chemical composition of fresh and ensiled forage, which affected the feeding value and in vitro rumen degradability, and the Amarillo and hybrid genotypes presented the best values in the evaluated parameters.