Plant extracts have been used over time in traditional medicine, mainly for their antimicrobial activity as well as for their medicinal effects. Plant-derived products contain secondary metabolites that prevent pathogenic microbial growth similar to conventional medicines. These secondary metabolites can enhance animal health and production in a more natural or organic manner and may contribute to the reduction in the use of pharmacological drugs in animal feed, which is of great concern for emerging microbial resistance. Plant secondary metabolites can be cost effective, while improving the production efficiency of ruminants, non-ruminants, and aquatic food animals. Among the plant-derived products is the Yucca schidigera extract (YSE), containing steroidal saponins as their main active component. YSE has multiple biological effects, including inhibition of some pathogenic bacteria, protozoa, and nematodes. YSE is used to control odor and ammonia and consistently enhance poultry production by enhancing intestinal health and function. In pigs, results are as yet inconclusive. In ruminants, YSE works against protozoa, has selective action against bacteria, and reduces the archaea populations; all these effects are reflected in the reduction in emissions of polluting gases, mainly methane, although the effects are not observed in all feeding conditions. These effects of YSE are discussed in this review. YSE has potential as a natural feed additive for sustainable animal production while contributing to the mitigation of contaminant gas emissions.

Introducción: El sistema vaca-cría consiste en la producción de becerros al destete para su posterior venta y engorde. En el Estado de Tabasco, un porcentaje alto de productores se dedica a esta actividad. Sin embargo, es poca la información que existe sobre este sistema de producción. El objetivo del presente estudio fue caracterizar el sistema de producción vaca-cría, e identificar los factores que afectan la producción de becerros en el Estado de Tabasco.Método: Para ello, se entrevistó a 342 productores, con base en una encuesta estructurada; con ella, se obtuvo información sobre datos del productor, características sociales, infraestructura, estructuras del hato, y prácticas productivas y de manejo. Para identificar los tipos de productores, se realizó un análisis de conglomerado por el método de Ward y distancia euclidiana al cuadrado; y para identificar las variables que explican la producción de becerros, se realizó un análisis de regresión lineal.Resultados: El análisis de conglomerado identificó tres tipos de productores: 1) pequeños; 2) medianos; y 3) grandes. El 63.4 % de los productores se clasificaron como pequeños (< de 14 vacas en producción); 29 % como medianos (entre 15 y 34 vacas en producción); y 7.6 % como productores grandes (entre 35 y 80 vacas en producción). En los tres tipos de productores, el número de vacas en producción, el índice de adopción de tecnología y la cantidad de alimento concentrado explican la producción de becerros.Discusión o Conclusión: La caracterización del sistema vaca-cría de regiones tropicales es importante, debido a que más de la mitad de la ganadería de dichas regiones utiliza este sistema de producción. Además, conocer los factores que determinan la producción de becerros puede ayudar a generar estrategias para el apoyo de este tipo de productores y mejorar las variables productivas del sistema.

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.

Introduction: Current diets of broiler chickens tend to increase protein levels to obtain high productive variables that are achieved in combination with genetic, management, and sanitary improvements, among others. An increase in dietary crude protein levels does not always accompany an increase in broiler productive efficiency due to multiple factors involved in the production system. The objective of this study was to evaluate the effect of increasing levels of dietary crude protein (CP) on productive performance, carcass characteristics, and chemical composition of breast and thigh meat in broiler chickens raised in the dry subtropics of northeastern Mexico.Method: The study used 200, 1-day-old male Ross broiler chicks. In a completely randomized design, birds were allocated to the four treatments with five replicates (floor pens) of ten birds each. The trial was divided in two phases (starter and finisher) of 21 days each (42 days total). Treatment diets (T) for starter and finisher phases had crude protein concentrations (CP; %) of 21 and 18.1 (T1), 21.4 and 18.5 (T2), 21.8 and 18.9 (T3), and 22.2 and 19.3 (T4), respectively. Within each feeding phase, the four treatment diets were formulated to similar levels of apparent metabolizable energy.Results: Protein concentrations had no effect (P > 0.05) on weight gain, while feed intake was greater in T1 (P < 0.05) than in T2 and T3. Feed conversion was better in T2 and T4 (P < 0.05) than in T1. There was no influence of treatment on carcass weight or carcass cuts (P > 0.05). Carcass yield was greater in T1 than in T3 (P < 0.05). Breast and thigh dry matter and ether extracts were similar (P > 0.05) between treatments. Breast crude protein was greater (P < 0.05) in T2 than in T3. The lowest (P < 0.05) CP concentration in thigh meat was in T3.Discussion or Conclusion: These results indicated that in the dry subtropics area of northeastern Mexico increases in CP above the level of T2 (21.4% and 18.5% CP in starter and finisher diets, respectively) did not improve broiler chicken productive performance, carcass characteristics or meat chemical composition.

The concentration of conjugated linoleic acid (CLA) in dairy products derived from ruminants, such as cow’s milk, is mainly influenced by the dietary lipid profile. The current study aimed to establish the relationship between fatty acid (FA) profiles in various diets and the concentration of...