AuthorNGOU NGOUPAYOU, JEAN DANIEL.
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PublisherThe University of Arizona.
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AbstractA series of experiments was conducted to evaluate the value of jojoba meals in chick, rabbit and laying hen diets. Treated meals used in these studies had been subjected to solvent, chemical and microbial treatments for the removal of simmondsin toxicants. Feeding 5% untreated jojoba meal diets to either chicks, rabbits or laying hens resulted in a general poor performance as evidenced by reduced feed intake, poor growth and poor feed conversion; in addition, low egg production and egg output were obtained with laying hens. Incorporation of the untreated meal (containing 4.7% simmondsin compounds) at 10% of the diet caused 55.6% mortality in chicks. A pair-feeding study with chicks revealed that reduced feed intake rather than toxic effects was responsible for decreased growth and mortality. A similar study with rabbits showed that both high levels of simmondsin toxicants and palatability were responsible for poor growth. Of the seven meals tested with chicks, only the Lactobacillus acidophilus #1911 treated meal supported adequate growth when added to the diet at a level of 10%. However, feed conversion was poor at this level of suplementation. Lowering the simmondsin toxicants to .34% of the meal allowed adequate growth in weanling rabbits when incorporated in the diet at levels up to 15%. Slightly lower amino acid digestibilities were obtained for diets containing this meal. Studies of amino acid availabilities with the jojoba meals indicated a general low availability for the essential amino acids (33.7% for lysine and 43.4% for methionine). Starch digestibility was also low (22%) and true metabolizable energy varied from 1.71 to 1.90 kcal/g in laying hens. Jojoba meal also contains a trypsin inhibitor (TI) with activities reaching 5.48 TIU/g which was inactivated in 30 min at 15% moisture and 100 C. Tannic acid levels in the jojoba meals varied from 1.50 to 2.57%. Poor amino acid availabilities were still obtained after TI inactivation. The use of jojoba meal in the feeding of poultry or rabbits will require the removal of the simmondsin toxicants, denaturation of the TI as well as consideration of the poor amino acid availability and low energy content.
Degree ProgramNutritional Sciences