Search

El objetivo fue evaluar, en pastoreo de praderas mixta de Medicago sativa L. y Dactylis glomerata L., la respuesta de vacas Holstein Neozelandés a la suplementación con concentrado en diferentes momentos del día, sobre producción individual, carga animal y producción de leche por hectárea. Se realizaron dos experimentos, en invierno y en primavera-verano, con un diseño cruzado 3×3. Los tratamientos fueron tres momentos de oferta de concentrado (5.0 kg de MS vaca-1 día-1) como suplemento luego de la ordeña matinal (AM), de la vespertina (PM), y dividido equitativamente en ambas ordeñas (AM-PM). Las unidades experimentales fueron lotes de seis (invierno) o cinco vacas (primavera-verano) y sus respectivas áreas de pastoreo, mismas que recibieron los tratamientos. El criterio de manejo del pastoreo rotacional fue 8 cm de altura de forraje residual para todos los tratamientos; esto permitió estimar el efecto de los tratamientos sobre la carga animal. No hubo efecto (P>0.05) sobre carga animal. La producción de leche por vaca en AM fue 10.2 % superior que los otros dos tratamientos en promedio, tanto en invierno (8.6 %, P=0.0002), como en primavera-verano (11.7 %, P

Objetivo. Determinar la dosis recomendable de bentonita como quelante de arsénico (As) y plomo (Pb) en el medio ruminal, abomasal y duodenal mediante un sistema in vitro, considerando las variables de fermentación ruminal y el efecto adsorbente de As y Pb. Materiales y Métodos. Se prepararon viales con 50 mL de medio anaerobio y 0.5 g de alfalfa como sustrato. Los medios se adicionaron con 1.01 y 1.95 ppm de As y Pb, respectivamente. Los tratamientos consistieron en el nivel de bentonita (B) adicionada al medio, B-0%, B-1.5%, B-3.0% y B-4.5%. Los medios se incubaron durante 24 h y se midió el pH, producción de AGV, N-NH3, degradabilidad in vitro de MS (DIVMS) y efecto quelante de la bentonita, simulando las condiciones del rumen, abomaso y duodeno. Se usó un diseño completamente al azar y contrastes ortogonales. Resultados. La bentonita no modificó el pH ni la proporción molar de AGV (p>0.05), pero la producción total de AGV presentó un efecto lineal negativo al aumentar el nivel del mineral. Asimismo, el N-NH3 disminuyó (p

Few studies have evaluated the impact of a lipid-rich diet with palmitic acid (PA) in ruminal fermentation. The objective was to evaluate the in vitro bath culture of the protected PA on the ruminal fermentative variables. Four diets were used: (a) without protected PA (nPA) and (b) inclusion of protected PA at three levels: PA3 = 3%, PA6 = 6%, and PA9 = 9% dry matter (DM). The maximum gas production occurred without including protected PA and the low gas production given with the inclusion of protected PA9 (p ≤ 0.05). Meanwhile, the inclusion with 3 and 6% of protected PA showed a higher level of gas production kinetics than the other treatments (p ≤ 0.05). DM and organic matter degradation after 72 h of incubation linearly decreased (p ≤ 0.05) with a high level of protected PA. The level of C16:0 in the protected AP increased with the higher level of supplemented AP (p ≤ 0.05). The best efficiency in propionic acid, decrease in methane, and increase in biohydrogenation (79%) occurred with the inclusion of protected PA3 (p ≤ 0.05). In conclusion, supplements with protected PA at 3 and 6% increased PA availability. The results indicate good benefits of protected PA on fermentative variables, and these doses seem ideal for future research in lactating goats.

Meat is an excellent medium for bacterial growth due to its high water and nutrient content. The nitrogenous compounds (NC) are derived through decarboxylation of amino acids due to microbial enzymes. The objective of this study was to evaluate the concentration of 3 NC and the proliferation of some microorganisms in rabbit meat with three treatments (T) , classified by three types of packaging for 21 days (d) in rabbit meat stored cold. The meat samples were obtained of the Longissimus thoracis et lumborum muscle. Each sample was divided and two groups were formed. The first group was used to measure the physicochemical characteristics of the meat, and the second group was used to quantify NC and bacterial isolation. The pH in the meat decreased from 0 to 21 d in the three T. The brightness (L*) decreased (P0.05). Putrescine (PU) increased (P

Por su importancia como cultivo estratégico de invierno parcialmente caracterizado, se estudió la composición química de avena forrajera variedad Chihuahua. En hoja, tallo, maleza, panícula y planta completa, se determinaron (g 100 g-1) fibra detergente neutro (FDN), fibra detergente ácido (FDA), lignina cruda (LC), cenizas (Cen), proteína cruda (PC) y grasa cruda GC), y se evaluaron sus correspondientes rendimientos (kg ha-1). La PC disminuyó (p < 0.05) y los contenidos de FDN, FDA y LC aumentaron (p < 0.05) en hoja, tallo, maleza y planta completa al avanzar la edad de corte. El contenido de GC aumentó con la edad en hoja y panícula (p < 0.05), pero no se observaron cambios en tallo ni en maleza (p > 0.05). En panícula el contenido de FDN disminuyó fuertemente, 21.6% y el de PC disminuyó levemente, 1.0% (p < 0.05), mientras que los de LC y GC aumentaron (p < 0.05) al avanzar la edad. Se detectó un máximo rendimiento de PC en hoja y maleza a los 75 días de edad, mientras que, en tallo el rendimiento máximo de PC se produjo a los 90 días. Para que el forraje de avena, variedad Chihuahua, no contenga tanta fibra y a fin de que los contenidos y rendimientos de proteína no sean tan bajos, se sugiere cosechar esta planta entre 75 y 90 días de edad.

Ruminants, mainly cattle, contribute to greenhouse gases (GHG) emissions as methane (CH4) is produced by ruminal fermentation. Hence, various anti-methanogenic feed strategies have been studied, including the use of plants with secondary metabolites. This study evaluated in vitro ruminal fermentation metrics, microbial composition by digital droplet PCR (ddPCR) and the CH4 production of the foliage of several tropical trees and shrubs: Leucaena leucocephala, Moringa oleifera, Albizia lebbeck, Enterolobium cyclocarpum, Piscidia piscipula, Brosimum alicastrum, Lysiloma latisiliquum, Guazuma ulmifolia, Cnidoscolus aconitifolius, Gliricidia sepium and Bursera simaruba, using Cynodon plectostachyus grass as control. The results showed a wide variation in the chemical composition of the foliage, as well as in the ruminal microbiota. The crude protein (CP) content ranged from 11 to 25%, whereas the content of condensed tannins (CT) and saponins (S) was from 0.02 to 7%, and 3.2 to 6.6%, respectively. The greatest dry matter degradability (DMD) after 72 h was 69% and the least 35%, the latter coinciding with the least gas production (GP). A negative correlation was found between the CT and CH4 production, also between protozoa and fungi with the SGMT group of archaea. We concluded that the foliage of some tropical trees and shrubs has a high nutritional value and the potential to decrease CH4 production due to its CT content.

The objective of this study was to evaluate the inclusion of oregano essential oil (OEO) as a phytogenic feed additive in the diet of lambs on the productive performance, ruminal pH, ammoniacal nitrogen production, volatile fatty acids, nitrogen balance, carcass yield, backfat thickness, loin eye (Longissimus dorsi) area, shelf life, and antioxidant activity of the meat. Thirty-nine Suffolk × Hampshire lambs (19 ± 3.7 kg live weight) were used in a completely randomized design with three treatments (n = 13) consisting of 0, 0.02, and 0.04% OEO in the diet. The inclusion of OEO in the diet did not affect (p > 0.05) the productive performance due to the treatments; similarly, no differences (p > 0.05) were observed in the ruminal variables and nitrogen balance. Backfat thickness and loin eye area had similar results (p > 0.05), and the antioxidant activity in meat was improved (p < 0.05) with the inclusion of OEO. Shelf life and crude protein content increased (p < 0.05) with the inclusion of OEO in the diet and with the passing of storage days. Dry matter was affected (p < 0.05) by the storage time, with a decrease observed on day 24. pH, ether extract, and ash were not affected (p > 0.05). It is concluded that the productive performance, ruminal variables, nitrogen balance, loin eye area, backfat thickness, and carcass yield were not affected by the inclusion of OEO. However, crude protein remained stable and antioxidant activity improved, increasing the shelf life of lamb meat.

Dicalcium phosphate (DP) is a mineral involved in the metabolism and development and is used as a dietary source of phosphorus (PT) for poultry. Our study objective is to design nano-dicalcium phosphate (NDP) by co-precipitation. The methodological procedure was divided into two phases: (1) NDP synthesis, and (2) bird performance, digestibility, and Ca-P in chick’s tissues. The sizes of the NDP were 20–80 nm. NDP had the Ca: P ratio of 1:1.12. The birds were divided into control diet (available P (Pa) = 0.13%) and three supplementary P sources [Commercial (Calcium phosphate), analytical grade (DP) and nanoparticles (NDP)] with three Pa levels (0.24, 0.35, 0.46%). Supplementary P sources compared to the control treatment had the highest body weight gain (698.56 vs. 228; p < 0.05) and feed intake (FI) (965.18 vs. 345.82), respectively. The digestibility of PT (67%) improved with 0.35% NDP. The highest contents of PT -breast were with the levels of 0.35 and 0.46% NDP. The PT, ash, and diameters were higher (p < 0.05) with supplementary P compared to the control treatment. As conclusion, the use of 0.35% NDP was the ideal dose in the chicks for the digestibility, absorption values, and the amount of PT in the breast.

ABSTRACT: Canola provides oil for human consumption and a by-product from the extraction of its oil canola meal (CM), is used as a good quality protein and lipid supplement for ruminants. The aim of this study was to determine the chemical composition and fermentation profile associated with the potential for methane production of three types of CM: solvent-extracted CM of Brassica napus (CMBN), B. juncea (CMBJ) and cold press-extracted CM from B. napus (CPCM) used to feed ruminants. The protein content of canola meal ranged from 36 to 41 %. The acid and neutral detergent insoluble in nitrogen ranged from 1 to 2 % and 4 to 5 %, respectively. The lipid content of canola meal samples ranged from 2 % (CMBN, CMBJ) to 14 % (CPCM). In vitro, dry matter disappearance of CMBJ was higher than that of other types of CM at 4 h, 24 h and 48 h. Gas production from CMBJ was greater than that of CPCM and CMBN at 24 h and 48 h of incubation. CPCM produced lower methane than CMBJ at 48 h of incubation. CPCM produced a higher (p < 0.05) molar proportion of propionate from 12 h to 48 h of incubation. In conclusion, this study found that CPCM could be a good source of protein (mainly PB2) and lipids in the feed of ruminants; it will decrease methane production and enhance propionate production. There was correlation between less methane production, and the content of lipids and PB2 in the three types of CM studied.

Background: The use of silages from non-conventional sources of nitrogen and soluble carbohydrates in feeding lambs is controversial in terms of nutrient supply; due to the minimum number of studies reported to date of in vitro evaluations that allow measuring its nutritional value in ruminants. Objective: To evaluate the additive effect and fermentation potential of silages plus concentrates in diets for lambs on the in vitro gas production kinetics. Methodology: Six diets (silage + concentrate) were evaluated in a factorial arrangement of 3 N sources (dried poultry litter, fresh swine manure, agricultural urea) × 2 carbohydrate sources (sugar cane molasses, bakery by-product). The diets contained: a) silage (400 g/kg DM) and b) concentrates (600 g/kg DM) based on soybean meal, ground corn, wheat bran, corn stover, fish meal, and vitamin and mineral premix. Average gas production data were analyzed with PROC MIXED and the gas production curves were fitted into the Exponential Logistic model with PROC NLMIXED. Results: The PO+MC (151.87 mL/gas MS) and CF+MC (153.12 mL/gas MS) treatments had higher average gas production during incubation. An additive effect was observed on the maximum asymptote of gas production in the CF+MC (+ 4.26%) and PO+MC (+ 3.75%) diets (P

Background. Ruminants have been related to greenhouse gas production. Therefore, it has been necessary to find alternatives by using natural additives to reduce their production by modulation of rumen fermentation. Objective. It was to evaluate the effect of the addition of condensed tannins (CT) and different levels of essential oregano oil (Lippia graveolens) (EOO) in sheep's diets on in vitro fermentation products such as total gas production, methane (CH4), carbon dioxide (CO2), pH, ammoniacal nitrogen (N-NH3), and volatile fatty acids (VFA). Methodology. There were evaluated six experimental diets: the control diet with 4% of CT kg/DM, and 0.02, 0.04, 0.06, 0.08 or 1% de EOO kg/DM, respectively. Total gas production, CH4, CO2, pH, N-NH3, and AGV were measured at different in vitro incubation times. Results. Total gas production was not affected (P > 0.05) due to treatment or the interaction treatment*time. An exponential increment was observed (P < 0.05) according to incubation time. CH4 and CO2 production increased at 48 h. The lowest emissions of these gases were recorded when 0.04, 0.06, 0.08, and 1% of EOO were added to the diet. Nevertheless, no differences were found (P > 0.05) due to treatment or the interaction treatment*time. Acetic and butyric acid concentrations were affected due to incubation time and the interaction treatment*time; however, there was no effect due to treatment (P > 0.05). Propionic acid production and pH were not affected (P > 0.05) due to treatment, time, or interaction treatment*time. N-NH3 production increased through incubation time (P < 0.05), with the highest concentration at 48 h for all treatments, without differences (P > 0.05) due to treatment or interaction treatment*time. Implications. These results suggest that the inclusion levels of TC and EOO in the diet were not enough to affect rumen fermentation or methane production. Therefore, it is necessary to evaluate higher levels of these compounds in sheep's diets. Conclusion. The addition of CT or the different levels of EOO included in sheep's diets evaluated in this study did not affect total gas production, CH4, CO2, pH, concentration of N-NH3, AGV, and pH.

Total antioxidant capacity (TAC) and physicochemical characteristics of meat were evaluated after supplementing different doses of propolis in broiler chickens’ diets at: 15, 30, 45 and 0 mg propolis/kg feed for Pr15, Pr30, Pr45 and Pr0, respectively. Two hundred one-day-old chickens were fed for 42 d and sacrificed. Breast meat samples were used for physicochemical determinations. Oxidative capacity was measured on days 0, 1, 3, 5, 7 and 9 of storage. There were no differences (P > 0.05) between the supplementation systems in either pH, luminosity index (L*), red (a*), yellow (b*), drip loss, cooking yield, protein, ash or moisture. Meat from chickens fed the highest propolis dose (Pr45) presented the lowest oxidative capacity (P