Ingestive behavior of finishing sheep fed detoxified castor bean meal

Submitted on July 25 , 2014 and accepted on January 20 th , 2016. Part of the Master Degree’s dissertation of the first author. 2 Instituto Federal da Paraíba, Sousa, Paraíba, Brazil. danielcezar.s@ig.com.br Instituto Federal da Paraíba, Sousa, Paraíba, Brazil. beatriz_dfernandes@hotmail.com; jessicamonique_318@hotmail.com; francisco.jocelio@hotmail.com Universidade Federal do Piauí, Departamento de Zootecnia, Teresina, Piauí, Brazil. miguel_arcanjomf@hotmail.com; arnaud@ufpi.edu.br *Corresponding author: daniel.cezar@ifpb.edu.br Ingestive behavior of finishing sheep fed detoxified castor bean meal 1


INTRODUCTION
The increase in the Brazilian demand for biodiesel as an alternative energy source has significantly raised the availability of co-products such as cakes, meals and bark, from the extraction of oil seed oils.In this scenario, the livestock sector is strategically positioned to use these potential feeds, which often represent low cost sources of protein and energy (Oliveira et al., 2010).
Among the several oil seed species, castor bean (Ricinus communis L.) has stood out in the Northeast region for representing an important promoter of economic and social development of small farmers (Brasil, 2005), a fact that was highlighted in 2008 when the inclusion of biodiesel in the composition of fossil diesel became compulsory, as determined by the National Programme for Production and Use of Biodiesel (ANP, 2009).
This determination has expanded the availability of coproducts of the extraction of oil from castor bean seeds, which, combined with the nutritional potential of these alternative ingredients, has allowed greater use for feeding purposes, as verified by Gowda et al. (2008), who found no differences between the control diet and those based on castor bean, obtaining from that the digestibility of dry matter, neutral detergent fiber and crude protein of 61.3; 58.6 and 58.1%, respectively.According to Silva et al. (2010), providing detoxified castor meal to sheep in finishing did not affect intake, fecal and urinary excretion, nitrogen absorption and retention by an average of 26.70; 10.9; 17.96 and 15.78 g/day, respectively, recommending the use of this co-product for feeding sheep, as it does not influence ruminal pH, the concentration of N-NH 3 in the rumen fluid and urea in blood serum.
Despite these results, animal performance cannot be assessed without taking into account the aspects of ingestive behavior, which are essential to the nutrient intake, digestibility and other nutritional parameters.According to Silva et al. (2004), the factors that affect ingestive behavior are linked to the diets, the environment and to the animal, with greater relevance to the first factor, especially when using agro-industrial co-products, which usually have variations in chemical composition or antinutritional factors.
For the co-products of castor bean, the restriction of use in animal nutrition is attributed to the presence of antinutritional factors, ricin, ricinine, complex allergen CB-1A (Aslani et al., 2007), but can be inactivated by detoxification processes, by temperature and pressure treating of the bran, in association or not with chemical agents (Anandan et al., 2005).
Therefore, because it presents these characteristics, the need for studying ingestive behavior of sheep fed detoxified castor meal is justified since this tool allows evaluation of diets aiming at adjusting the feeding management of animals, in order to obtain better performance, compared to the use of unconventional diets.
The objective of this study was to evaluate the effect of substituting soybean meal on by detoxified castor meal the ingestive behavior of sheep in finishing.
Total isoprotein and isoenergy diets were evaluated for sheep in finishing.Those diets contained castor bean meal substituting soybean meal at levels 0, 33, 67 and 100%, on the dry matter basis.The diets were composed by elephant grass (Pennisetum purpureum Schum.)cv.Roxo hay, processed at 90 days of sprout, and concentrate composed disintegrated corn grain, soybean meal, urea, mineral vitamin supplement and castor bean meal, detoxified by autoclaving at 121°C under pressure of 15 psi for one hour (Anandan et al., 2005), with the chemical composition shown in Table 1, aimed at meeting the nutritional requirements recommended by the NRC (2007) for average daily gain of 200 g (Table 1).
After that, an in vivo metabolism trial was carried out, using 20 Santa Inês crossbred sheep, not castrated, with initial body weight of 35 ± 5 kg at eight months of age, in good health and nutritional status, kept in cages of metabolism study, with dimensions of 1.0 x 0.5 m.Animals were fed experimental diets offered at 8 a.m. and 4 p.m., which were provided so to provide 15% of leftovers foi influenciada (P > 0,05), com médias de 4,31 e 1,84, respectivamente.A substituição do farelo de soja pelo FMD diminui o tempo em alimentação quando da utilização em 60%, mas não influencia o consumo de MS e FDN, o tempo despendido em ruminação, em ócio, e o TMT.O uso de 60% de FMD eleva a eficiência de alimentação de MS e FDN e não compromete a eficiência de ruminação.
In the beginning of the experiment period, the animals were weighed after fasting, for distribution in treatments according to a randomized block design with four treatments (diets) and five repetitions (sheep), adopting the change in body weight in the beginning of the experiment for distribution of animals in the five blocks.
To determine the intake, the in vivo total collection method of leftovers was used for seven days, preceded by a period of 14 days for the animals to get adapted to experimental conditions.The leftovers were collected before each meal, withdrawing an aliquot of 20%, which were then placed in plastic bags and stored in a freezer (-5 to -10°C).At the end of the collection period, samples of the leftovers were defrosted, homogenized and composite samples per animal were formed.The daily intake of dry matter and nutrients was estimated by the difference between the offered diet and leftovers.
Samples were analyzed at the Laboratório de Nutrição Animal (LANA) of the Departamento de Zootecnia (DZO / CCA / UFPI).Samples of leftovers were dried at 55 °C in an oven with forced air circulation for 72 hours and ground in a Wiley-type mill to reduce them to 1-mm particles.Contents of dry matter (DM) were determined and, based on them, the neutral detergent fiber (NDF), according to methods described by Silva & Queiroz (2002).
The evaluation of the ingestive behavior of sheep was performed for three consecutive days, during the experimental period, quantifying the time spent in feeding, ruminating and idle for 12 hours per day, according to the adaptation of the methodology of Macedo et al. (2007).
Observations were carried out from 6 a.m. to 6 p.m. at every 30 minutes, using scam sampling by four trained observers in a turn system, strategically placed so not to disturb the animals.
Ingestive behavior parameters, the time spent eating, ruminating and idle, were expressed in minutes/12 h, while the feeding efficiency (FE) and rumination efficiency (RE) were expressed in grams of dry matter (DM) and neutral detergent fiber (NDF) per minute/12 h, calculated by the following relationships: FE DM = DMI/FT and FE NDF = NDF/ FT, FE DM = DMI/RT and RENDF = NDF/RT, where DMI = daily dry matter intake (g); NDF = daily neutral detergent fiber intake (g), TF = time spent in feeding minute/12 hours and RT = time spent ruminating minute/12 h.
The total chewing time (TCT minute/12 h) was obtained using the formula: TCT = FT + RT where FT = time spent in feeding minute/12 h and RT = time spent in rumination minute /12 h.
Data were analyzed according to PROC MEANS procedure of SAS statistical software (2001), carrying out descriptive statistics for means, standard deviation and coefficient of variation.Regression analysis was performed using the PROC GLM where the parameters of feeding behavior were considered as dependent variables and the substitution levels 0; 33; 67 and 100% of detoxified castor bean meal substituting soybean meal as independent variables for the construction of the models.*TCHO = total carbohydrates and *NFC = non-fibrous carbohydrates, estimated according to Sniffen et al. (1992).

RESULTS AND DISCUSSION
Dry matter (DM) intake was not influenced (P > .05)by the replacement of soybean meal by detoxified castor bean meal (DCBM) in diets, with means of 1362.6 g / animal/day (Table 3) , which allowed meeting nutritional requirements for DM intake established by the NRC (2007), of 1003.00 g/day.
The values obtained in this study for DM intake corroborate those verified by Vieira et al. (2011), who found no significant difference for this parameter when substituting soybean meal by detoxified castor bean meal at the levels of 0; 50; 75 and 100% with respective means of 1550; 1490; 1530 and 1490 g/animal/day, confirming that the use of this co-product in the feeding of sheep does not limit DM intake.
The substitution of soybean meal by detoxified castor bean meal did not affect neutral detergent fiber (NDF) intake (P > .05)(Table 2), with a mean of 582.98 g/animal/day.When NDF intake was related to body weight, it was found that its amount corresponded to 1.47% of body weight and did not affect dry matter intake.
The average levels of NDF in the diets, from 41.43% in DM (Table 1), with 28.17% of NDF from the roughage, and NFC of 33.63% in the DM, denoting an adequate diet to a good stability of fermentation conditions in the rumen.Levels of NDF in the experimental diets can be considered high; however, they did not affect the intake parameters of DM and OM, considered determinants of animal performance, unlike that verified by Cardoso et al. (2006), in whose work, the rise of dietary NDF levels impaired the intake of DM and nutrients.
The time spent in rumination and idle, and the total chewing time (TCT) were not influenced (P > .05)by the participation of detoxified castor bean meals in the diets, with means of 181.33; 347.04 and 366.24 minutes/12 h respectively, contrary to time spent in feeding, which was influenced (P < .05)and resulted in a quadratic effect (P < .05),with a minimum of 164.56 minutes/12 h, when 60% of detoxified castor bean meal was included in the diet (Table 2).
The reduction in the time spent in the feeding, due to the greater participation of that meal from the referred co-Table 2: Means and regression equations for DM and NDF intake (g/animal/day), time spent in feeding, rumination, idle and total chewing time (TCT) (minutes/12 h), feeding and rumination efficiency (g DM and NDF/minute and h/12 h) in sheep fed diets containing detoxified castor bean meal substituting soybean meal.product in the diets, may be attributed to the significant difference in NDF content between soybean meal (13.27%DM) and detoxified castor bean meal (38.26%DM) (Table 3), which conditioned greater effect of NDF on feeding time, resulting in an increase in the time spent for the performing this ingestive activity.These results are confirmed by observations of Hübner et al. (2008), who found a decrease in time spent in feeding, from 255.00 minutes/day to 222.50 minutes/day when the level of NDF was increased from 43 to 52%, on a dry matter basis in the diet of lactating ewe.

Detoxified castor bean meal (DCM
In the evaluations of the ingestive behavior of Morada Nova crossbred sheep, fed diets containing levels of detoxified castor bean meal similar to those evaluated in this study, Vieira et al. (2011) found an interaction between the evaluation periods and the time spent in activities of feeding, rumination and idle.In this situation, the shortest feeding time was observed in animals receiving diets with 0 and 100% of substitution of soybean meal by detoxified castor bean meal, in the period from 17 to 20 hours.Carvalho et al. (2006), when evaluating ingestive behavior of Santa Inês sheep fed co-products, found no effect on the parameters of ingestive behavior, with the animals remaining at 22.16; 43.77 and 34.06% of the time eating, ruminating and at idle, respectively, contrary to what happened in this study, in which the time spent in feeding activities represented 27.8%; the rumination time was 25.18% and the idle time was 48.2%.
Feeding efficiency in function of the DM and NDF were influenced (P < .05)by the substitution of soybean meal by detoxified castor bean meal, which resulted in a quadratic effect, with maximums of 4.43 g DM/minute and 2.08 g NDF/minute when 58.8 and 69.5% of detoxified castor bean meal were included in the diet, respectively (Table 2).
The rise in feeding efficiency for DM and NDF at the substitution levels previously mentioned, shows that the detoxified castor bean meal does not seem to compromise the feeding behavior, because even with the reduction in time spent in feeding, the feeding efficiency has not decreased, indicating that animals compensated for the shortest time spent on feeding activity, keeping the amount of feed consumed in the 12 hours of daily assessment, confirmed by the lack of effect (P > .05)for DM intake (Table 2).
This result can be even justified by feeding period, which was influenced (P < .05)by the levels of detoxified castor bean meal and resulted in a quadratic effect (P < .05),with a minimum of 5.59 feeding periods, when 62% of the coproduct was included in the diet (Table 2), indicating a virtual increase of feeding efficiency for DM and NDF, since the sheep reduced the access to the trough, but increased in proportion to the amount of food ingested at each access.
Rumination efficiency, in g DM and NDF/minute was not influenced (P > .05)by the substitution levels of soybean meal by detoxified castor bean meal, with averages of 4.31 and 1.84, respectively (Table 2) , which may be linked to the fact that diets are ground, thus reducing the possible effects of DM and, above all, the NDF on rumination events.
The values obtained in this study for rumination efficiency in g DM/h corroborates those verified by Vieira et al. (2011), who found no significant difference for this parameter when soybean meal was substituted by DCBM at the levels of 0; 50; 75 and 100% with respective means of 198.06; 202.75; 197.14 and 224.19 g DM/hour.

CONCLUSIONS
The substitution of soybean meal by detoxified castor bean meal reduces the time spent in feeding when using 60% in the diet, but does not influence the intake of DM and NDF, the time spent on rumination and idleness, and total chewing time, with recommendation of using up to this level, by raising the feeding efficiency of DM and NDF and did not compromise the rumination efficiency.*TCHOT = total carbohydrates and *NFC = non-fiber carbohydrates, estimated according to Sniffen et al. (1992).

Table 1 :
Percent and bromatological composition of diets with detoxified castor bean meal substituting soybean meal

Table 3 :
Chemical composition of the ingredients in the experimental diets