INTRODUCTION

Food is one of the items with the highest incidence in costs in production units, supplementation is very important in this area, where the price of food and product, will define the level and supplement use period. From the production and processing of food for humans, numerous by-products and residues originate that can be used for animal feed (supplements); which have different nutritional characteristics according to their origin and the type of industrial processes to which they were subjected; in general they present the peculiarity of being very concentrated in one or more nutrients (proteins, lipids, carbohydrates, etc.); so they can be combined with other foods in balanced diets for animal feed (^{INTA, 2002}).

The elaboration of balanced foods in the production of animals requires ingredients that cover their biochemical and energy needs; the most used raw material for energy-protein intake is corn and soybean meal; however, in our days, this can be a limitation, due to the costs generated by its use in the preparation of food (^{Al-Tulaihan et al., 2004}); for this reason, non-traditional alternatives have been sought, which provide lower cost and greater flexibility in the formulation; among which we can mention energy raw materials, which at least partially replace cereals, since currently the demand for cereals for human and animal consumption has increased; reflected in an increase in the production costs of feed, (^{Catalá-Gregori et al., 2011}).

Some researchers have been inclined towards these alternatives for the fattening of animals, as they are the waste of bakery in substitution of corn or sorghum in the fattening of pigs (^{Cárdenas, 2012}), organic waste in the production and reproduction of dairy cows (^{Losada-Custardoy et al., 2016}) and cookie flour to feed broilers (^{Catalá-Gregori et al., 2011}). Biscuit flour is a by-product of the food industry, from the recycling of products for human consumption, which is increasingly used in the food industry of animals; its base component is wheat flour and can be considered a source of energy, given its high content of digestible carbohydrates and higher fat content than cereals; however, its composition and nutritional value may vary among suppliers (^{Waldroup et al., 1982}), depending mainly on the quality of the initial product and processing conditions (^{Catalá-Gregori et al., 2011}).

These alternatives can be used in various animal productions, among which we can mention rabbits. The production of rabbit in small and medium scale presents certain advantages over other species, due to its speed of reproduction and its digestive physiology, which allows them to adapt to diets rich in structural carbohydrates (^{Lara et al., 2012}); In addition, rabbit meat has several advantages with respect to the meat of other species, has a better profile of fatty acids in conjunction with the amount of protein, vitamins and minerals; its low content of cholesterol and sodium, coupled with the lack of uric acid (^{Para, 2015}); Despite the qualities described above, its consumption and production is relatively low, the per capita consumption fluctuates between 30 and 134 g per person per year.

The rabbit production in the country is centralized in Hidalgo, Puebla, Mexico and Guanajuato states (^{Armada, 2016}). It has also been recognized that various governmental and non-governmental institutions encourage the production and consumption of this meat, either fresh or through various meat products. However, one of the main problems of rabbits, as in other animal species, is the cost of feeding.

The objective of this research was to evaluate the effect that the inclusion of biscuit waste in the food has on the productive parameters, the quality of the carcass and the meat in the fattening of rabbits.

MATERIAL AND METHODS

RESULTS AND DISCUSSION

The inclusion of biscuit waste in rabbit feed did not show significant statistical difference (p> 0.05) over the productive parameters (Table 2); which coincides in research with other species, as found in ^{Catalá-Gregori et al. (2011)}, who included biscuit flour in the fattening of broilers, without showing significant statistical difference over the productive parameters. ^{Cárdenas (2012)} substituted maize or soybean for bakery waste in diets for lambs without finding significant statistical differences in the productive parameters; however, they were able to reduce feeding costs. The values obtained for final weight were higher than that obtained by ^{Khan et al. (2016)}, when using alfalfa hay and concentrated.

Regarding the quality of the meat and the carcass of rabbits that were fed with biscuit waste as an energy source, there were no significant differences (p> 0.05) (Table 3 and 4), as was found by ^{Alagón et al. (2015)} when feeding distillers dry grains to rabbits from 49 to 59 d of age, without having an effect on the carcass. Also, in chickens by ^{Catalá-Gregori et al. (2011)}, that did not observe differences in the broiler carcass fed with cookies flour in the diet. It should be mentioned that the animals that consumed food that included cookies waste in their diet showed a tendency to present greater weight in viscera (Table 4). In regard to pH, including cookies waste, the pH of the meat was not modified, unlike what was found by ^{Alagón et al. (2015)}, who when including dry distillery grains in the diet of fattening rabbits saw an increase in this measure.

CONCLUSION

The results obtained suggest that the inclusion of biscuit waste as an energy substitute for corn or soybean paste is a viable option for rabbit production, because it does not alter the productive parameters and the quality of meat and carcass; In addition to being a cheaper option, which would affect a substantial improvement in the production of rabbits.