Animal Science

Production of steers fed African oil palm (Elaeis guineensis L.) fiber with the addition of organic minerals and grazing Africa star grass

A. Gómez-Vázquez^{1  *}  , Alejandra Govea-Luciano¹  , E. De la Cruz Lázaro¹  , A. Cruz Hernández¹  , C.A. Álvarez González²  , Nancy Patricia Brito Manzano¹  , Arely Bautista Galvez³  , C. C. Alfonso Juventino¹  , J.A. León Nájera¹ 

¹División Académica de Ciencias Agropecuarias, Universidad Juárez Autónoma de Tabasco. Carretera Villahermosa-Teapa km 25, México

²División Académica de Ciencias Biológicas. Universidad Juárez Autónoma de Tabasco. Carretera Villahermosa-Teapa km 25, México

³Escuela Maya de Estudios Agropecuarios. Universidad Autónoma de Chiapas, México

Abstract

The effect of the addition of an organic mineral (Bioplex Quality Meat) and a complement of African oil palm fiber as supplementary forage in the gain and digestibility of fattening steers in grazing under tropical conditions was studied. A total of 40 crossbreed steers (Bos taurus x Bos indicus), with average initial live weight of 276 ± 28 kg for 120 d were used. They were fed individually with 1 kg d-1 of concentrate (14 % CP) and African oil palm fiber. A completely randomized design was applied, according to the following treatments: 1)control, only grazing (CG); 2) grazing + African oil palm fiber (AOPF-0); 3) grazing + African oil palm fiber + 15 g animal-1 d-1 of Bioplex Quality Meat (AOPF-15) and 4) grazing + African oil palm fiber + 30 g animal-1 d-1 Bioplex Quality Meat (AOPF-30). The daily weight gain of the steers was improved with Bioplex Quality Meat, with a linear effect (P <0.01); (CG =492, AOPF-0 = 554, AOPF-15 = 637, AOPF-30 = 792 g d-1 Bioplex Quality Meat). This was associated with the increase in intake (linear effect P <0.05) of African oil palm fiber (CG = 0.0, AOPF- 0 = 3.06, AOPF-15 = 3.08, AOPF-30 = 3.36 kg d-1) and higher DM digestibility (P <0.05) with respect to the control group (CG = 67.13, AOPF-0 = 74.26, AOPF-15 = 72.29, AOPF-30 = 72.46 %).There was no effect on total forage or DM intake. It is concluded that Bioplex Quality Meat increases the nutrient availability of the African oil palm fiber, which improves the daily weight gain.

Key words: organic minerals; African oil palm; steers; digestibility

The feeding of cattle in tropical regions is based on the use of grasses, whose biomass and nutritional quality show seasonal variations, which is reflected in animal productivity. For this reason, various nutritional strategies have been proposed, such as protein-energy supplementation, access to protein banks and the use of complementary cut forages (^{Ramos et al. 1998}, ^{Rojo et al.2000}, ^{Aranda et al. 2001} and ^{Pérez et al. 2001}). In this context, the African oil palm fiber has great importance as a potential resource, due to its acceptable digestibility of the protein (75 %) (^{Ocampo et al. 1990}).

It is also of great interest the use of organic minerals in ruminants nutrition, since it has been shown that the efficiency in the use of the fibrous fraction of food can be improved (^{Ocampo et al.1990}). From this perspective, the researches has focused on evaluating the organic minerals in forages of temperate climate, but there has been poor or virtually null the information generated in tropical regions, where forages have lower nutritional value.

Most of the studies about grazing supplementation are carried out with limited amounts of grains and nitrogen compounds, in order to obtain the best use of the forage resource. However, animal production depends more on the availability of forage than on the type of complement (^{Cabrera et al. 2000}). That is why the supplementation with agricultural by-products, such as the African oil palm fiber, is a viable management alternative to maintain animal production during critical periods of lack of forage, due to floods or drought. The use of organic minerals, jointly with protein supplements, can be an alternative to obtain better use of African oil palm fiber.

The objective of this study was to evaluate the effect of an organic mineral, added to the African oil palm fiber, on the digestibility and weight gain of steers that graze Africa star grass.

Materials and Methods

An experiment with 40 crossbreed steers Bos taurus x Bos indicus, with average initial live weight of 276 ± 30 kg for 120 d, distributed in four treatments with ten repetitions, in a completely randomized design was carried out. The research was performed in Zermeños farm, located in "Los Jinetes" area, belonging to Macuspana municipality, Tabasco. This facility is at 17º 59 '22 "north latitude; 99º 24 '19 "west longitude and altitude of 20 m o.s.l, with climate Am (f)" (i') gw ", warm humid; with rains in summer, temperatures of 26.2 ºC, 1868.9 mm of rainfall and 80% annual average relative humidity (^{García 1981}).

The steers were fed individually with African oil palm fiber (AOPF), and were distributed in the following treatments: 1) Control, only grazing (CG); 2) CG + African oil palm fiber (AOPF); 3) CG + AOPF + 15 g animal-1 d-1 of Bioplex Quality Meat (AOPF-15) and 4) CG + AOPF + 30 g animal-1 d-1 Bioplex Quality Meat (AOPF-30). The amount of mineral was offered in two equal portions individually (7.00 am - 7.00 pm). A 1 kg animal-1 d-1 of concentrated food (table 1) was used as a vehicle to ensure that the steers ingested the mineral. At the beginning of the experiment they were applied dewormer (Ivomecq, 1 mL per 50 kg-1 LW) and ADE vitamins (1 mL per 50 kg-1LW). The African oil palm fiber was milled in a stationary chopper.

At 5:00 p.m., the young bulls were confined in individual pens to receive the African oil palm fiber. The animals from the control treatment (only grazing) were returned to the grassland, while the rest remained in individual pens until 7 a.m. After this time they were taken to graze in the grasslands of Africa star grass until 6:00 p.m. Mineral salts were also offered (15.8 % Ca, 6.83 % P, 4.38 % K, 0.02 % Mg, 1.75% S, 0.07 % Mn, 0.03 % Cu, 0.15 % Zn, 0.01 % Fe, 11.45% Na, 2.63 ppm Co, 4.38 ppm Se, 36.75 ppm) and free access water.

Table 1 Composition of the food used in the steers fattening¹ 

¹Values informed by the enterprise“La Ganadera” from Villa Hermosa Tabasco

An amount of 0.5 kg of concentrate with 7.5 and 15 g of enzyme were offered mixed in the food according to the treatment, plus 40 g of mineral salt (20 g in the morning and 20 g in the afternoon). The African oil palm fiber was immediately supplied.

Eight paddocks were used with African star grass (Cynodon plectostachyus); with a total area of 4 ha, delimited with electric fence; the days of the grassland occupation varied from 4 to 6, depending on the availability of the forage, with a stocking rate of 6 steers ha-1. The palm fiber was offered ad libitum. Rejections were daily weighed to quantify the actual daily intake of the steers and samples were taken from the forage offered and rejected from the grasslands (before and after the grassland was grazed, to evaluate the availability of DM).

On day 105 of the experiment, the steers received 5 g d-1 of chromium oxide (Cr₂ O₃ ) orally, in a period of 15 d, to evaluate the digestibility and intake of the ingredients. Faeces samples were collected in PolyPaper bags, in the last five days at 07:00 hours. Samples were dried at 50 °C in a forced air oven until constant weight was reached and ground in a Willey mill with a 1 mm sieve. In the analysis of the samples of the experimental diets, the following components were determined: dry matter at 100 ºC and ash (combustion at 600 ºC), nitrogen according to Microkjeldahl (^{AOAC 2016}), neutral detergent fiber (NDF), acid detergent fiber (ADF) and crude protein mixed to the acid detergent fiber (CP-ADF) according to ^{van Soest et al. (1991)}. Chromium was determined by atomic absorption spectrophotometry (^{Williams et al. 1962}) and acid insoluble ash (AIA) according to ^{van Keulen and Young (1977)}. The daily intake of the African oil palm fiber (DIAOPF, kg) was calculated by subtracting the palm fiber offered and rejected every day during the experimental period. Grass intake was evaluated by the technique of two markers, chromium oxide and acid insoluble ash (^{Geerken et al. 1987} and ^{Aranda et al. 2001}), fitted by indigestible marker intake of the African oil palm fiber and the supplement, as is show in the following equation:

$\text{Intake DM forage =}\frac{{\text{(AIA)}}_{\text{H}}{\text{x TFP}-[{(AIA)}}_{\text{S}}{\text{x SI}-{(AIA)}}_{\text{FP}}\text{x FI}]}}{{\text{(AIA)}}_{\text{P}}}$

where:

(AIA)H	- Concentration of acid insoluble ash (AIA) in faeces (g kg^-1 DM)
TFP	- Total faeces production obtained with Cr2O3, as external marker (g d^-1).
(AIA)S	- AIA concentration of the supplement (g kg^-1 DM).
SI	- Daily supplement intake (g).
(AIA)FP	- AIA concentration in the African oil palm fiber (g kg^-1 DM).
FI	- Daily intake of African oil palm fiber (g day^-1).
(AIA)P	- AIA in the grass (g kg^-1 DM).

The daily fecal DM production was calculated according to the formula described by ^{Church (1988}):

${\text{Fecal DM production (g d}}^{\text{-1}}\text{)=}\frac{{\text{Marker dose (g d}}^{\text{-1}}\text{)}}{{\text{Marker concentration in faeces (g g}}^{\text{-1}}\text{DM)}}$

The digestibility of the DM intake was evaluated using the methodology proposed by ^{Geerken et al. (1987}), in which first the total digestibility (grass+supplement) is obtained by the difference between the total intake (grass+ supplement) and the fecal DM production (^{Church 1988}). The digestibility of the grass was obtained when evaluating the digestibility of the supplement to 85%, according to the following formula:

$\text{DMD of grass=}\frac{\text{(DMST) - (DMDS) (DM contribution of the supplement)}}{\text{DM contribution of the grass}}$

where:

DMD	- Dry matter digestibility, %
TDMD	- Total dry matter digestibility, %
DMDS	- Dry matter digestibility of the supplement, %

The in situ digestibility of Africa star grass, palm fiber and concentrate was determined with nylon bags. These were incubated for 12, 24, 48, 72, 84 and 96 h in bulls cannulated in rumen (^{Vanzant et al. 1998}). For the daily weight gain (DWG, g), the bulls were weighed every 20 d for four consecutive days, with a previous fast of 12 h, recording the mean of this variable. The average final weight (AFW, kg) was obtained at the end of the experimental period, with the cumulative weight of the steers in each of the treatments. The feed conversion (FC, kg) was calculated with the algebraic relation of digestible DM intake (DDMI) and DWG. Linear and quadratic effects were tested with mineral levels (^{Draper and Smith 1981}). The data were analyzed with a completely randomized design (^{Steel and Torrie 1980}) with the GLM (^{SAS 1985}) procedure and the use of the initial weight as a covariate and P <0.5.

Results and Discussion

The intake of African oil palm fiber showed linear effect (P <0.001) when increasing the organic mineral level of 3.36 kg DM animal d-1 for 30 g of Bioplex Quality Meat with respect to the treatment without the addition of organic mineral, which was 3.06 kg DM animal d-1, without affecting the forage intake (table 2).

The total DM intake was high for each treatment (table 2), which is attributed to the equilibrium state of chromium oxide and food (^{Mendoza et al. 1995}), since it was only supplied in a single intake, which could affect the estimation of the parameters. This shows that the intake estimation in supplemented animals, with or without AIA fitted, underestimates approximately 1 kg to the actual intake (^{Shipley and Clark 1972}). If the conditions of any marker are not in equilibrium, the estimation of fecal matter can be underestimated or overestimated, because the input and outputs rates of the marker are not real, which results in incorrect estimates of intake (^{Mendoza et al.1995}).

Table 2 Nutrient intake of steers that graze Africa star grass and intake complement with African oil palm fiber and an organic mineral 

DMD = Dry matter digestibility; DDMI = digestible dry matter intake; LE = Linear effect; QE = Quadratic effect.

^**p<0.001; NS: Not significant.

^abcdMeans with different literals within the rows differ (P <0.05).

The possibility of evaluating the use of controlled release capsules to estimate the intake of grazing animals could be considered (^{Parker et al. 1989}) and the evaluation of several internal indigestible markers, such as chromogens, lignin, INDF or IADF, silica, alkanes, among others should be considered too (^{Kotb and Luckey 1972}, ^{Nelson et al. 1990} and ^{Sunvold and Cochran 1991}). The negative effect on the NDF digestion does not occur in combinations with African oil palm fiber (^{Ocampo et al.1990}).

The African oil palm fiber without organic mineral did not affect the in vivo digestibility, compared to the control (table 2). The limiting factors in African palm oil fiber intake are the high concentration of NDF, its slow digestion rate and the prolonged time of ruminal retention (^{González et al. 1991}, ^{Aroeira et al.1993} and ^{Figueira et al. 1993}), which resulted in this study much higher (52 to 73 h) than those reported by ^{Poppi et al. (1981}) for tropical grasses (32 to 45 h). ^{Figueira et al. (1993)} reported mean ruminal retention time values of 52-60 h for sugarcane DM supplemented with urea, a figure that is similar to that obtained in African oil palm fiber. If a mineral supplement in African oil palm fiber has a limited effect on the NDF digestibility (^{González 1995}), the organic minerals are an option to obtain more nutrients from the cell walls of African oil palm fiber.

The organic minerals (Bioplex Quality Meat) increased the intake of African oil palm fiber and improved the NDF digestion (table 2). The low NDF digestibility of African oil palm fiber has been associated with the slow reduction of particle size and the prolonged residence time of the particles in the reticulum-rumen, due to the high concentration of lignified cell walls with low digestibility (^{Molina 1990}). Bioplex Quality Meat is a complex of a combination of zinc protein and yeast enriched with chromium and selenium.

When the control received African palm oil fiber, it did not modify the DM or NDF digestibility. However, the addition of the organic mineral improved the NDF and DM digestibility (table 2). The substitution of Africa star grass with African oil palm fiber affected in vivo digestibility when it was included from 0 to 21%. This is comparable with sugarcane, since it shows similar performance due to its high fiber content (^{Aranda 2000}). Therefore, it is confirmed that there is no negative associative effect of the soluble oils impregnated in African oil palm fiber on the digestibility, as ^{Sutton (1979}) and ^{Leng (1989}) refer. The organic minerals improve the NDF digestibility, complemented with the cellulolytic activity of the rumen microorganisms, and allowed the steers to ingest more DM (^{Lewis et al. 1996} and ^{Oba and Allen 1999}). Tropical forages have a low digestibility, if they are compared with those of temperate climate. Therefore, the effect of these additives can be important on the use of low quality forages.

When the dose of the organic mineral increased, the NDF digestibility improved significantly (table 2). Therefore, the in vivo digestibility of the NDF was higher for steers which received the highest dose (30 g) of the organic mineral (P <0.01), showing a quadratic associative effect (P <0.01). This indicates that the organic mineral can be used in grazing systems where forage is the main dietary component.

Regarding the productive performance of the steers, a linear effect (P <0.02) of the organic mineral was observed on daily weight gain and feed conversion (table 3). The daily weight gain (DWG) with African oil palm fiber was similar to that obtained in the control group, with the high level of organic mineral, which indicates that without the mineral there would be a substitute effect, as reported by ^{Aranda et al. (2001}) for the case of sugarcane. However, the response with the organic mineral showed a linear effect (P <.001), which indicates that the DWG improves as a result of the higher intake of total digestible nutrients. The daily weight gain obtained in this experiment is higher than those reported by ^{Aranda et al. (2001)}, when studying heifers in grazing that intake sugarcane treated with urea without enzymes, with a stocking rate of 6 heifers ha-1. This implies that the African oil palm fiber is an agricultural by-product capable of replacing cutting grasses in tropical areas.

Table 3 Productive response of steers grazing African Star grass and a complement with African oil palm fiber and the addition of an organic mineral. 

DWG (g d-1) = Daily weight gain; FC =Feed conversion; AFW =Average final weight; LE = Linear effect; QE = Quadratic effect.

*p<0.05; **p<0.001

^abcdMeans with different literals within the rows differ (P <0.05).

It has been shown that lignification is one of the factors that influence on the digestion rate of cell walls, but there are other intrinsic that have not been identified (^{van Soest 1982}, ^{Mertens 1993} and ^{Weimer 1996}), so they are suggested as an object of future studies on African oil palm fiber. These factors are associated with the individual rate of degradation of structural carbohydrates or the proportions of arabinose and glucose of rapid degradation with xylose and slowly degrading uronic acids (^{Dekker et al. 1972} and ^{Ben-Ghedalia and Rubinstein 1984}).

Conclusions

The supplement with African palm oil palm fiber and the addition of an organic mineral (Bioplex Quality Meat) improved the weight gain of steers that graze the Africa star grass, due to the higher intake of digestible nutrients of palm fiber. When considering the main nutritional limitations of palm fiber (digestibility and nitrogen content), with the combination of complement and the use of organic minerals, higher nutrients can be obtained from palm fiber and incorporated as complementary food under tropical conditions.

Acknowledgments

Thanks to Fundación Produce Tabasco A.C. for the financing of this project. It also expresses gratitude to the producers of African oil palm from Jalapa Municipality, Tabasco, who contributed with the African oil palm fiber and to the directors of the DACA-UJAT for the facilities provided during the performing of this research.

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Received: March 16, 2017; Accepted: February 18, 2018

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