Call number: LD2668 .T4 1956 O77 / Master of Science

Call number: LD2668 .T4 1961 S87

Call number: LD2668 .T4 1964 B57 / Master of Science

Call number: LD2668 .T4 1964 M68 / Master of Science

Call number: LD2668 .T4 1979 C59 / Master of Science

Call number: LD2668 .T4 1965 M43 / Master of Science

A 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.

Effects of tallow supplementation on dietary nutrient and minimal amino acid utilization in the laying hen were studied in two experiments. In the first experiment diets contained six levels of animal tallow ranging from 0 to 10%. Percent egg production and egg mass were not significantly affected by tallow. Body weight was significantly increased by 2% tallow was maximum at 6%. Addition of up to 6% fat improved feed conversion without adversely affecting other production characteristics. Metabolizable energy (ME) intake increased from 305.1 to 322.4 kcal/hen/d over the range of 0 to 6% tallow with no further improvement at higher tallow levels. Maximum net energetic efficiency was obtained with 2 and 4% tallow. Ability to digest tallow declined significantly with hen age. Higher tallow ME values were obtained from calorimetry data than from digestibility measurements due to beneficial effects of tallow on digestibilities of fat and protein in the basal diet. No improvement in starch retention was observed with tallow supplementation. In the second experiment, diets containing four levels of protein (15.0, 13.6, 15.0 + methionine and 17.0%) without and with 3% tallow were fed to hens housed in an open cage house or an insulated, evaporatively cooled house. Egg production and egg mass were significantly higher in the insulated house. This study indicates that reducing total protein below the National Research Council (NRC, 1984) recommended level significantly reduced egg production by birds housed in an open house. Supplemental methionine to provide .60% TSAA was required for maximum egg production. Egg production was significantly improved with the low protein diet when 3% tallow was added; however, egg production rate supported by this combination was significantly below that obtained with the 17% protein diet either with or without added tallow. For birds housed in the insulated, evaporatively cooled house the diet based on the NRC amino acid recommendations appeared to be optimal for performance, even with a lower protein level. No additional benefits were obtained in egg production with 3% tallow in any of the diets under these housing conditions.

No description available.

Digitized by Kansas Correctional Industries