Dietary salt and round heart disease in turkey poults with a note on the minimum level of supplementary salt necessary in corn-soybean diets

Round heart disease in turkey poults has been associated with high levels of dietary salt and when it occurs in the field recommendations often include a reduction in the level of dietary salt. Poults fed diets containing up to 1.5% salt and 1.5% sodium did not exhibit signs of round heart disease. A high mortality rate occurred with poults fed a salt-free diet. Post-mortem analysis generally revealed enlargement of the kidneys with urates; exudate was present in both abdominal and thoracic air sacs. Growth trials indicated that in order to maintain an optimum feed:body weight gain ratio, corn-soybean diets should contain at least 0.1--0.2% supplemental salt, and at least 0.2--0.3% salt when growth rate is considered. Minimum salt levels could not be reduced further by adjustment of the total dietary sodium:chloride ratio to unity.

Arginine-lysine relationship in rapeseed meal

A series of experiments was conducted using White Leghorn male chicks to study the arginine-lysine relationship in rapeseed meal (RSM). Semi-purified diets containing 15% protein either from RSM or soybean meal (SBM) were fed. Arginine supplementation completely reversed the growth depression caused by the addition of lysine to RSM diets. Potassium acetate was only partially effective in alleviating the growth depression caused by supplemental lysine, while polyvinyl pyrrolidone significantly reduced chick performance. Tannic acid addition (1.5%) to SBM diets resulted in a severe growth depression which was partially corrected by the supplementation of arginine in the presence of methionine. Supplementation of these amino acids to RSM had a less drastic effect. It is suggested that a portion of the arginine in rapeseed meal may be required for metabolic processes involved in tannic acid excretion.

Calcium and phosphorus requirements of the laying hen

Three experiments were conducted; the first studied the influence of pre-laying dietary calcium levels on subsequent hen performance, while in the second and third the influence of various levels of dietary calcium and phosphorus on performance, egg shell quality and calcium and phosphorus retention were investigated. Pre-dietary calcium levels (0.5 and 1.5%) resulted in a significant strain X diet interaction for weight gain up to commencement of lay but did not influence production, feed intake, egg size or sheel quality. Dietary calcium levels varying from 2.5 to 4.0% did not significantly alter the avove parameters during a 140 day laying test. Compared to a non-pelleted control diet, steam pelleting resulted in a significant enhancement in phosphorus availability is judged by higher levels of performance. Percent calcium retention varied with the level of dietary calcium and there was an indication that level of dietary phosphorus influenced calcium retention. Lower levels of dietary phosphorus resulted in egg shells with slightly lower deformation values. Regardless of dietary phosphorus, retention values were quite low. Changing the level of dietary calcium and phosphorus had little or no effect on the retention of phosphorus thus suggesting a relatively constant and low requirement for this nutrient.