Artículos de investigación

 

Inclusión de heno de chícharo (Pisum sativum L.) y producción de gas in vitro en dietas para corderos en crecimiento

 

Inclusion of field pea hay (Pisum sativum L.) and in vitro gas production in diets for growing lambs

 

Ulises Alejandro González García¹, Manuel González Ronquillo^1*, Julieta G. Estrada Flores², Jorge Luis Bastida García¹, Nazario Pecador Salas¹, Abdel-Fattah Z.M. Salem¹

 

¹ Departamento de Producción Animal. Facultad de Medicina Veterinaria yZootecnia.

² Instituto de Investigación en Ciencias Agropecuarias y Rurales. Universidad Autónoma del Estado de México. Toluca. México. Instituto Literario No 100, Col Centro. CP 50000. E-mail: mrg@uaemex.mx

* Corresponding Author

 

Submitted April 11, 2011
Accepted July 08, 2011
Revised received August 23, 2011

 

Resumen

La utilización de subproductos agroindustriales como el heno de chícharo (Pisum sativum) es una alternativa para la alimentación de ovinos, el objetivo del presente estudio fue evaluar la ingestión y digestibilidad en ovinos alimentados con diferentes niveles de inclusión de heno de chícharo (HC). Para ello se utilizaron 20 ovinos con un PV inicial de 26.0 ± 0.43 kg, los cuales fueron alimentados con uno de cuatro tratamientos (0%; 25%; 50% y 75% de inclusión de HC en base seca). El contenido de PC del HC fue de 8%. No se observaron diferencias significativas (P>0.1) entre tratamientos para la ingestión de MS (947.57 ± 32.25 g/d^-1), MO (856.74 ± 24.76) y FND (583.46 ± 30.6), así como para la digestibilidad (g/100g) de la MS (50.32 ± 1.0), MO (49.4 ± 2.38) y FND (57.04 ± 2.23). El consumo de N fue menor (P<0.05) para el tratamiento con 25 % HC con respecto a 0%, no se observaron diferencias (P>0.1) para la excreción de N en heces, orina y el balance de N entre tratamientos. En la producción de gas in vitro la fracción A (mi gas/g MS incubado) fue menor para HC con respecto a rastrojo de maíz (RM) y maíz grano (MG). La fracción b fue mayor (P<0.05) para HC respecto a los demás ingredientes, sin embargo no se encontraron diferencias (P>0.1) entre RM y MG para la fracción c. La producción de gas relativa (ml gas/ g MS desaparecida) fue menor para HC con respecto a RM y MG, La MS desaparecida in vitro fue menor para HC con respecto a MG, sin embargo no se encontraron diferencias (P>0.1) entre RM y HC. El heno de chícharo puede ser utilizado en dietas para ovinos hasta en un 75 % de inclusión, sin afectar la ingestión y digestibilidad. La técnica de producción de gas in vitro permite predecir la fermentación y degradación ruminal, mostrando una menor fermentación con un 25 % de inclusión de heno de chícharo.

Palabras claves: Corderos; Comportamiento productivo; Heno de chícharo; Producción de gas invitro.

 

Abstract

The use of byproducts such as field pea {Pisum sativum) is an alternative to feed sheep, the objective of this study was to evaluate the intake and digestibility in sheep fed different levels of field pea hay (FPH). Twenty Rambouillet lambs (with an initial BW of 26.0 ± 0.43 kg) were fed to one of four treatments of 5 animals of each (0%, 25%, 50% and 75% inclusion of PH as dry matter basis). The content of CP for the FPH was 8%. There were no significant differences (P>0.1) between treatments for DM intake (947.6 ± 32.3 g/d), OM (856.7 ± 24.8) and NDF (583.5 ± 30.6), as well as digestibility (g/lOOg) of DM (50.3 ± 1.0), OM (49.4 ± 2.38) and NDF (57.0 ± 2.23). N intake was lower (P<0.05) for PH 25% compared to 0%, no significant differences (P>0.1) for N excretion in feces, urine and N balance between treatments. In vitro gas production in the fraction A (ml gas / g DM incubated) was lower in FPH compared to corn stover (CS) and corn grain (CG). Fraction b was higher (P <0.05) for FPH compared to the other ingredients, however there were no differences (P>0.1) between CS and CG for fraction c. Gas production (ml gas / g DM disappeared) was lower in FPH compared to CS and CG. In vitro DM disappearance was lower for FPH with respect to CG, however there were no differences (P>0.1) between CS and FPH. FPH can be used in diets for sheep up to 75% of inclusion, without affecting intake and digestibility. The gas production technique allows the prediction of in vitro fermentation and rumen degradation, showing a lower fermentation with 25% inclusion of FPH.

Key words: Lambs; Productive behavior: Field pea hay; in vitro gas production.

 

INTRODUCTION

The apparent digestibility of foods is essential to establish its nutritional value and, therefore, for the formulation of rations in the ruminants. However, the determination of in vivo digestibility is a laborious and expensive process, requiring the use of large amounts of food, so different methods have been proposed for estimating in vitro (Bochi-Brum et al., 1999). In vitro studies can be carried out with a large number of samples in a relatively short time, providing information on rates of digestion (Aimone et al., 1977). The interest in using agricultural waste in feed for ruminants has been increasing worldwide in recent years, as the availability of grains is reduced (Fuentes et al., 2001). There is a large amount of agricultural residues and agro-products (straw, stubble, stalks, etc.) that could be used as an alternative source of energy and protein in feed for ruminants. An example of these products is field pea hay (FPH) (Pisum sativum), which is left in the plot after harvesting pea pods without a rational as it would feed (Bastida Garcia et al., 2011). In Mexico's annual pea production is approximately 48031.76 ton met/ year, and the State of Mexico produces 8.13% of total production (http://www.siap.gob.mx), however, does not have a record of the remaining residue obtained after the last harvest, because not all waste is used for animal feed.

Some authors indicate a dry matter intake an efficient feed conversion and daily weight gain is similar when pea hay replaces cereals in growing and finishing diets of cattle (Reed et al., 2004), but there are few studies in sheep (Bastida Garcia et al., 2011). It was reported that the nutritional characteristics of these feed resources depress feed intake, digestibility, rate of fermentation and microbial nitrogen supply (Mekasha et al., 2003) and because nitrogen is a limiting nutrient in low-quality forages, supplementation with protein nitrogen sources or non-protein nitrogen have been used for the supply of ruminal ammonia level to meet the requirements of microbial protein (Fondevila and Barrios, 2001; Manyuchi et al., 1997).

The aim of this study was to evaluate the productive performance of growing lambs fed different levels of inclusion of FPH and estimate rumen fermentation from in vitro gas production.

 

MATERIALS AND METHODS

Animals and diets

The study was conducted in the Faculty of Veterinary Medicine at the Autonomous University of Mexico State, were used twenty Rambouillet lambs, with an average age of 5 months and 26.0 ± 0.43 kg BWi distributed homogeneously according to their weight in 4 groups of 5 animals each one. The animals were housed at random to each of the 4 treatments (Table 1) to be evaluated by considering treatment as a witness and three inclusion levels of FPH (0%, 25%, 50% and 75%). Diets were iso-protein and iso-energy (13.26% CP and 8.8 MJ ME kg DM) based on forage (pea hay: FPH; corn stover: CS) and concentrate (Corn grain: CG, soybean meal, SBM and fishmeal: FM) supplemented with vitamins and minerals (Multitec of Malta ®), the chemical composition of the ingredients is presented in Table 2, diets were formulated according to the recommendations proposed by the AFRC (1996), meeting the needs of animals for their level of growth. The FPH used for this study was obtained from the field after the last harvest (3^rd crop) seed pea. The FPH was milled using a hammer mill (mill Azteca, 5 mm Ø). The concentrate and forage ratios were mixed homogeneously to prevent the selection of ingredients, using a vertical mixing mill (mill Azteca).

 

 

Intake and apparent digestibility

Sheep were housed in metabolic cages (1.20 x 0.80 m) with an individual fed at 0800 and 1600 h and having free access to drinking water, food intake and the residues were weighed daily. The experimental period lasted 28 days, 21 days for diet adaptation and 7 days for sample collection. Samples of feces and urine were collected daily in its entirety and they took 10%. The feces were placed in plastic bags and urine containers where there was a mixture of samples taken per animal and frozen at -20 °C for further analysis. After the experimental period proceeded to estimate voluntary food intake, food conversion, feed efficiency and digestibility.

 

In vitro gas production

To determine the kinetics of ruminal degradation, it was used technique of in vitro gas production according to the method proposed by Menke et al. (1979) and modified by Theodorou et al. (1994). Approximately 0800 g DM of each ingredient and each diet mixtures were incubated in glass flasks with 90 ml of buffer solution and 10 ml of rumen fluid having a replica of three bottles per sample. Three Rambouillet lambs (BW 20 ± 0.5 kg) cannulated in rumen as a fluid donor, which were fed ad libitum (0900 and 1600 h) with a diet based on alfalfa hay and straw oats in a 50:50 ratio, to which was added 2% of a vitamin and mineral supplement. About 0.5 L of rumen fluid and 100 g of rumen solid (0830 h) were collected from each lamb, extracted and filtered in triple layer of gauze and cheese cloth, and was homogenized with CO₂ for five minutes, then were mixed and used as inoculum. The flasks were incubated in a water bath at 39 °C. The volume of gas was recorded at 3, 6, 9, 12, 24, 36, 48, 72 and 96 h of incubation using a Delta brand pressure transducer (Model 8804 HD). After incubation the samples were filtered and dried (48 h, 65 °C) to measure the proportion of dry matter disappeared (DMD). Gas production at 96 h was correlated with dry matter disappeared for relative gas production (RGP: ml gas g DMD) (González Ronquillo et al., 1998).

Gas production was adjusted according to the model proposed by France et al. (1993) y = A [1 - exp (-b (t -T) - c (√ t - a/ T))]. Where: "y" is the cumulative gas production (ml) "t" is the incubation time (hours), A is the curve asymptote (total gas produced, ml), b (h-1) c (h - ½) are the constants of gas produced, T is the delay time (hours) that colonize the microorganisms to begin the fermentation. The values shown in Figures 1 and 2 were obtained from gas production split between the hours reading for each of the ingredients and diets.

 

Chemical composition

The DM content of feed, refusals and feces was determined in a forced air oven (60 °C, 48 h), and then milled (mill Willey, 3 mm Ø Arthur H. Thomas Philadelphia, PA) to determine organic matter (OM) AOAC (1991), and total nitrogen (N) by the kjeldahl procedure (AOAC, 1991), neutral detergent fiber (NDF) was determined according to Van Soest (1991) adding sodium sulfite and alpha amylase, using a digester fiber ANKOM. Urine samples were subjected to the determination of nitrogen (N) (AOAC, 1991). Residues from the in vitro incubation were dried (60 °C, 48 h) to determine the DM disappeared at 96 h.

 

Calculations and Statistical Analysis

Feed intake was the difference in the amount of feed offered and refused each day. The daily weight gain was calculated based animal weight every seven days until the completion of the experiment; the animals were weighed the morning before fasting the day before. Feed conversion was calculated by dividing the dry matter intake between daily gain and feed efficiency by dividing the daily weight gain between the daily intake. The relationship forage: concentrate ratio (F:C) was obtained considering the forage intake multiplied by 10 between the total intake (g /d) (Bastida Garcia et al., 2011).

To test in vivo, we performed an analysis of variance using a completely randomized design. Y ijk = μ + Tj + εijk. Where: μ is the overall mean, T is the effect due to treatment, ε is the experimental error.

For the in vitro study conducted an analysis of variance, which included treatment (n = 4) and repetition (3 rounds of incubation). The corresponding variance analysis was done using the GLM procedure of SAS program (1999). Comparisons between means were performed using Tukey's test (Steel and Tome, 1997).

 

RESULTS AND DISCUSSION

Intake and apparent digestibility

Table 1 shows the chemical composition of experimental diets. The content of CP for the FPH was similar to that found by Mekasha et al. (2003) who evaluated several products, including field pea, however, was less than that found by Garcia Bastida et al. (2011) using diets containing FPH, containing 16% CP at second cut, this last quotation that the court used the second FPH. The NDF content was lower than found by Rotger et al. (2006) who in assessing digestibility FPH, mentioned a value of 82%, possibly due to containing a few pods and leaves because they came from three cuts of the product, however was higher than that found by Gilbery et al. (2007) using FPH diets for cattle. The content of CP and NDF in the CS was lower than found by Fuentes et al. (2001), who report a CP content of 490 g / kg DM and 724 g / kg DM of NDF, this may be due to lignification of hay to be packed, with respect to CG, CP content was less than reporting Oropeza et al. (1989) who found 12% in different hybrids of corn, however, about the NDF content is no different to that found in the present study with 1.4%.

The chemical compositions of experimental diets are presented in Table 1. The CP content was higher for 75% inclusion of FPH, being less than that found by Bastida et al. (2011) and Abdel-Magid et al. (2008) who found a concentration of 13.7% of CP using the same inclusion of FPH in diets for sheep. The NDF was higher for the control treatment, because it contained CS, however, the concentration of NDF in all treatments was higher than that found by Pol et al. (2009), Loe et al. (2004) and Bastida Garcia et al. (2011) who reported a concentration of NDF in the range of 381.6 to 553.7 g / kg DM.

The daily weight gain, feed efficiency and feed conversion (Table 3) were not affected by the inclusion of pea hay in the diet (P>0.1), no clutch, although no significant difference, the animals were fed the diet containing 75% inclusion of FPH have a better efficiency compared to other treatments.

Table 3 shows the DM intake, which was lower than found by Loe et al. (2004) of 115 g/kg^0.75, and higher than that reported by Salawu et al. (2002), who reported 53.7 g/kg^0.75 of intake. OM intake did not differ (P>0.1) among treatments, while OM intake was increased with 25% inclusion of FPH, however, it was higher (P <0.05) than that found by Salawu et al. (2002) using pea hay field third cut in diets for lambs with 52 g/kg^0.75 of intake. The NDF intake showed no significant differences (P> 0.1) in treatments, however, differ from that found by Mekasha et al. (2002) using field peas in diets for lambs (49.24g/kg^0.75). With regard to the average values of ingestión (g/d) and balance and digestibility (g/100g) there were no significant differences (P>0.1) among treatments.

In regard to digestibility of different treatments, DM digestibility was similar to that found by Mekasha et al. (2002) using FPH, digestibility of OM in the present study was lower than found by Gilbery et al. (2006) of 65% using field peas in diets for cattle. The digestibility of NDF was higher than found by Meshaka et al. (2002) who found a digestibility of 45.8% using pea hay in diets for sheep, but differs from Reed et al. (2002) with a 75.5% digestibility of NDF when replacing 100% of the corn with field peas in diets for growing calves.

 

Nitrogen balance

The results obtained of nitrogen balance are shown in Table 4. N intake (g/d) was higher (P <0.05) with the inclusion of 25% of FPH compared to 75%, without differences (P>0.1) among other treatments, being higher than the found by Mekasha et al. (2002) and Salawu et al. (2002), who recorded a intake of 9.1 and 11.3 g N/d with field pea diets for lambs, this is because diets that included forage used only for their studies, which makes the N intake was less, however, the results obtained in this study were lower than found by Abdel-Magid et al. (2008) who reported a intake of 24.8 g N/d using diets for growing lambs. Fecal excretion shows no difference (P>0.1) among treatments, being lower than found by Mekasha et al. (2002) and Abdel-Magid et al. (2008), with an excretion of 6.85 g N/d which assessed various agro-products including field pea, and 7.82 g N/d using FPH in diets for growing lambs, this may be that in this study used FM and SBM, which are used as protein source on passage to be better used in the intestine (Guada, 1993). The loss of N in urine did not differ (P>0.1) in treatments being higher than that found by Mekasha et al. (2002) who show a loss of N of 1.13 g N/d, however, are less than Abdel-Magid et al. (2008) with an excretion of 11.97 g N/d. Regarding the N retained no differences (P>0.1) among treatments. The diets used in this study were made isoenergetic and isoproteic for which there were no differences between intake and digestibility, coupled with a low concentration of CP and NDF in forages used. The minimum N excretion in urine and feces found in this study indicates a greater utilization of nutrients, which reduces environmental pollution (soil) excess N excreted into the environment, avoiding being made nitrous oxide (N₂O), which contributes to the greenhouse effect (Elizondo, 2006).

 

In vitro gas production

Table 5 presents the parameters of gas production adjustment obtained in vitro incubation of the different ingredients used in the experimental diets, which shows that the fraction A (ml gas / g DM incubated) was lower for FPH with respect to CS and CG, the latter who showed the increased production of gas. The fraction b (h^-1) was higher (P <0.05) in FPH compared to the other ingredients, however there were no differences (P>0.1) between CS and FM for the fraction c (h^1/2). The lag time phase, FM and SBM had a higher start of fermentation compared to the other ingredients. Relative gas production (ml gas / g DMD) was lower in FPH compared to CS and CG. The DMD in vitro was lower for PH with respect to CG, but no differences (P>0.1) between CS and FPH, on the other hand, the DMD between CS and FM were not significantly different (P>0.1). The ability of rumen bacteria to degrade to a greater extent than the structural soluble carbohydrates (fodder) has been evidenced in the literature, as reflected in the production levels of gas or DMD (Bastida Garcia et al. 2011). Relative gas production was lower (PO.001) in FPH compared to the other ingredients, with the CG that has the highest amount of gas production.

Figure 1 shows the gas production of up to 96 hours of the ingredients used in the experimental diets, SBM results in increased production of gas to the first 3 h and found no difference (P>0.1) between remaining ingredients, at 3 and 6 h the CS showed a higher production compared to the other ingredients, this is due to the maturation stage of the cut stubble as the first cut, the leaves and stems contain a number low fiber which indicates containing rapidly fermentable soluble components in these parts (leaves and stems) so it has a higher gas production in the early hours of fermentation and then decline rapidly (Tolerates et al., 1999) , from 12 h onwards, the largest gas production is presented by the CG. The low gas production of the CG in the initial time of incubation compared with the other ingredients is due to increased slowly fermentable carbohydrate (Hamid et al., 2007), but the production of the FPH although it was lower compared to CS and CG has a constant gas production, this may be related to the content of hemicellulose in FPH, which is more available than in the CS which presents unions linked to the lignin that makes it less digestible (Bach et al., 2006). The FM gas production shows a lower gas production with respect to other ingredients used, this may be due to increased temperature during preparation, in which the proteins are denatured by breaking hydrogen bonds and disulfide bonds responsible for their secondary structure, the result of the distortion, reduces the solubility of the protein as well as susceptibility to degradation and rumen fermentation (Guada, 1993).

Table 6 shows the fermentation parameters of the different levels of inclusion of FPH in the diets, showing that the total gas production for 25% FPH was lower compared to the control diet (0% FPH). The average rate of degradation (h) shows that 50% of FPH was lower (P <0.05) compared to other treatments, but no significant differences (P>0.1) between 25 and 75%. For the fraction h^1/2 and lag time there were no differences (P>0.1) between treatments. It has been shown that the production of gas is related to the disappearance of the NDF (Nsahlai et al., 1995) and about Pell et al. (1997) found that the relationship between variables is linear with a slope remarkably constant. Also found a high correlation between in vitro gas production and availability of starch in cereal grains (Posadas et al., 2005). Gas production was higher on the diet containing 50% of FPH compared with other treatments, while the diet containing 25% of FPH inclusion had the lower value. For the DMD no differences were found (P>0.1) between treatments.

Figure 2 shows the gas production at different levels including the FPH, it was noted that gas production at 3, 6 and 9 h of incubation was higher (P>0.1 in the treatment that no containing FPH (0%) compared with the other diets, the production of gas at 3 h shows no significant difference (P>0.1) between treatments containing 25, 50 and 75% inclusion of FPH, with respect to the 6 h gas production was lower (P> 0.1) for the diet containing 50% compared with 25 to 75% of FPH which show no significant differences (P>0.1), compared to 12 hours of incubation, there was no significant differences (P>0.1) among treatments, the production of gas from 24 h onwards was lower (P>0.1) for the diet containing 25% of FPH with respect to the 50 and 75%. Usually as the starch in corn is more digestible than the NDF is expected that the substitution of concentrate feed by resulting in an increase in total digestibility of the ration, thus an increase in the fermentation as in diet with 25% inclusion of FPH, without clutch, although the potential for fiber digestibility of grasses is higher, the high rate of passage through the rumen resulting in higher effective fiber digestibility in legumes in grasses (Bach et al. 2006; Guada, 1993; Hoffman et al., 2007).

 

CONCLUSIONS

Pea hay can be used in diets for sheep up to 75% inclusion, without affecting intake and digestibility. The method of in vitro gas production is a useful tool for selecting ingredients for balancing rations, and the data obtained from the digestibility provide an adequate and reliable estimate of the nutritional quality of food.

 

ACKNOWLEDGEMENTS

This work was funded by the CONACyT through project No. I 37 568-B, the Universidad Autónoma del Estado de Mexico (UAEM) and Fundación Produce State of Mexico. The MC Jorge Luis Bastida and Ulises Alejandro González García were fiinded by a grant from CONACyT.

 

REFERENCES

Abdel-Magid, S.S., Abd El-Rahman, H.H., Mohamed, M.I. and Awadalla, I.M. 2008. Utilization of Chick Pea Straw and Pea Straw in Feeding Growing Rahmani Lambs. Journal of Agriculture and Environment Science. 4 (2):214-217.         [ Links ]

Aimone, J.C. and Wagner, D.G. 1977. Micronized Wheat. II. Influence on in Vitro Digestibility, in Vitro Gas Production and Gelatinization. Journal of Animal Science. 44:1096-1099.         [ Links ]

Bochi-Brum, O., Carro, M.D., Valdés, C, González, J.S. and López, S. 1999. In vitro digestibility of forages and concentrates: effect of the diet of donor animals. Archivos de Zootecnia. 48:51-61.         [ Links ]

Bastida Garcia.J.L., González Ronquillo, M., Dominguez, V.I.A, Romero, B.J. and Castelán, O. O. 2011. Effect of field pea (Pisum sativum L.) level on intake, digestion, ruminal fermentation and in vitro gas production in sheep fed maintenance diets. Animal Science Journal Japanese, doi: 10.1111/j. 1740-0929.2011.00884.x (in press).         [ Links ]

Bach, A. and Calsamiglia, S. 2006. La fibra en los rumiantes: ¿Química o física? XXII Curso de especialización Fundación Española para el Desarrollo de la Nutrición Animal (FEDNA).         [ Links ]

Elizondo, S. J. 2006. El nitrógeno en los sistemas ganaderos de leche. Agronomía Mesoamericana. 19:69-77.         [ Links ]

Ewing, W.N. 1997. The Feeds Directory. Commodity Products Guide.. Context Publications, Santa Rosa, CA. pp. 118        [ Links ]

Fondevila, M., Barrios, U.A. 2001. La técnica de producción de gas y su aplicación al estudio del valor nutritivo de los forrajes. Revista Cubana de Ciencia Agrícola. 35:197-206.         [ Links ]

Fuentes, J., Magaña, C, Suarez, L., Peña, R., Rodríguez, S., Ortiz de la Rosa, B. 2001 Análisis químico y digestibilidad "/'« vitro" de rastrojo de maíz (Zea mays L.). Agronomía Mesoamericana. 002:189-192.         [ Links ]

Gilbery, T.C., Lardy, G.P., Soto-Navarro, S.A, Bauer, ML. and Anderson, V.L. 2007. Effect of field peas, chickpeas, and lentils on rumen fermentation, digestion, microbial protein synthesis, and feedlot performance in receiving diets for beef cattle. Journal of Animal Science. 85:3045-3053.         [ Links ]

Guada, J.A. 1993. Efectos del procesado sobre la degradabilidad ruminal de la proteína y almidón. IX Curso de especialización Fundación Española para el Desarrollo de la Nutrición Animal (FEDNA. Barcelona).         [ Links ]

Hamid, P., Akbar, T., Hossein, J. and Ali, M.G. 2007. Nutrient Digestibility and Gas Production of Some Tropical Feeds Used in Ruminant Diets Estimated by the in vivo and in vitro Gas Production Techniques. American Journal of Animal and Veterinary Sciences. 2:108-113.         [ Links ]

Loe, E.R, Bauer M. L., Lardy, G.P., Berg, P.T. and Moore, B.L. 2000. Effect of field pea (Pisum sativum) replacement of corn in lamb finishing diets. Small Ruminant Research. 3:39-45.         [ Links ]

Loe, E.R., Bauer, ML., Lardy, G.P., Catón, J.S. and Berg, P.T. 2004. Field pea (Pisum sativum) inclusion in corn-based lamb finishing diets. Small Ruminant Research. 53:39-45.         [ Links ]

Manyuchi, B., Hovell, F.D., Ndlovu, L.R, Topps, J.H., Tigere, A. 1997. The use of groundnut hay as a supplement for sheep consuming poor quality natural pasture hay. Animal Feed Science and Technology. 69:17-26.         [ Links ]

Mekasha, Y., Tegegne, A., Yami, A., Umunna, N.N. and Nsahlai, IV. 2003. Effects of supplementation of grass hay with non-conventional agro-industrial by-products on rumen fermentation characteristics and microbial nitrogen supply in rams. Small Ruminant Research. 50:141-151.         [ Links ]

Mekasha, Y., Tegegne, A., Yami, A. and Umunna, N.N. 2002. Evaluation of non-conventional agro-industrial by-products as supplementary feeds for ruminants: in vitro and metabolism study with sheep. Small Ruminant Research. 44:25-35.         [ Links ]

Menke, K.H. and Steingass. 1988. Estimation of energetic feed value obtained from chemical analyses and in vitro gas production using rumen fluid. Animal Research and Development. 28:7-55.         [ Links ]

Mosier, A.R., Duxbury, J.M., Freney, J.R., Heinemeyer, O., Minamik, K. 1996. Nitrous oxide emissions from agricultural fields: Assessment, measurement and mitigation. Plant and Soil. 181:95-108.         [ Links ]

Nsahlai, I.V., Umunna, N.N. and Negassa, D. 1995. The effect of multi-purpose tree digesta on in vitro gas production from napier grass or neutral-detergent fibre. Journal of the Science of Food and Agriculture. 69:519-528.         [ Links ]

Hoffman, P.C., Lundberg, K.M., Bauman, L.M., Randy, D. Sha., Contreras-Govea, E.F. 2007. Digestibilidad in vitro del FDN (fibra detergente neutro): El debate de 30 vs 48 horas. Focus on Forage. 5:16-20.         [ Links ]

Oropeza, E.; Ortiz de Bertorelli, L. 1989. Evaluación nutricional de la proteína del grano de seis cultivares de maíz {Zea mays L.). revista de la facultad de agronomia-UCV (Maracay). 15:225-234.         [ Links ]

Pell, A.N., Doane, P.H. and Schofield, P. 1997. In vitro digestibility and gas production. In: Simposio sobre Tópicos Especiáis em Zootecnia, Lavras, GC,pp.lO9-132.         [ Links ]

Pol, M.V., Hristov, A.N., Zaman, S., Delano, N. and Schneider, C. 2009. Effect of inclusion of peas in dairy cow diets on ruminal fermentation, digestibility, and nitrogen losses. Animal Feed Science and Technology. 15:95-105.         [ Links ]

Posada S. L., y R. R. Noguera. 2005. Técnica in vitro de producción de gases: Una herramienta para la evaluación de alimentos para rumiantes. Liv. Res. Rural Development 17:36. http://www.cipav.org.co/lrrd/lrrd17/4/posa17036.htm. (Consulta: Enero 2010).         [ Links ]

Reed, J.J, Lardy, G.P., Bauer, M.L., Gilbery, T.C. and Catón, J.S. 2004. Effect of field pea level on intake, digestion, microbial efficiency, ruminal fermentation, and in situ disappearance in beef steers fed forage-based diets. Journal of Animal Science. 82:2185-2192.         [ Links ]

Reed, J.J., Lardy, G.P., Bauer, M.L., Gilbery, T. C, and Catón, J.S. 2004. Effect of field pea level on intake, digestion, microbial efficiency, ruminal fermentation, and in situ disappearance in beef steers fed growing diets. Journal of Animal Science. 82:2123-2130.         [ Links ]

Rotger, A., Ferret, A., Calsamiglia, S. and Manteca, X. 2006. In situ degradability of seven plant protein supplements in heifers fed high concentrate diets with different forage to concentrate ratio. Animal Feed Science and Technology. 125: 73-87.         [ Links ]

Salawu, M.B., Adesogan, A.T., Fraser, M.D., Fychan, R. and Jones, R. 2002. Assessment of the nutritive value of whole crop peas and intercropped pea-wheat bi-crop forages harvested at different maturity stages for ruminants. Animal Feed Science and Technology. 96:43-53.         [ Links ]

Servicio de Información Agroalimentaria y Pesquera. Informe 2009. Producción Nacional Annual de Chícharo. http://www.siap.gob.mx/index.php?option=com_wrapper&view=wrapper&Itemid=350.(Consulta: Julio 2011,         [ Links ])

Tacón, A.G.J., 1997. Fishmeal replacers: review of antinutrients within oilseeds and pulses - a limiting factor for the aqua feed green revolution? In: Tacón, A., Basurco, B., (Eds.), Feeding Tomorrow's fish. Cahiers Options Mediterraneennes 22. Instituí Agronomique Mediterraneen de Zaragoza, Spain, pp. 153-182.         [ Links ]

Theodorou, M.K., Williams, B.A., Dhanoa, M.S., Me Allan, A.B., France, J. 1994. A simple gas production method using a pressure transducer to determine the fermentation kinetics of ruminant feeds. Animal Feed Science and Technology. 48:185-197.         [ Links ]

Tolera, A. and Sundstól, F. 1999. Morphological fractions of maize stover harvested at different stages of grain maturity and nutritive value of different fractions of the stover. Animal Feed Science and Technology. 81:1-16.         [ Links ]

Young, N.E. 2002. The Forages and Protein Crops Directory, pp. 25. Context publications, Leicestershire, UK        [ Links ]