Mimeo AS-287 August, i960 Progress Report
Purdue University Agricultural Experiment Station Lafayette, Indiana
THE EFFECT OF ARSANILIC ACID ON THE PROTEIN REQUIREMENT OF THE GROWING PIG l/
J. H. Conrad, D. M. Whitaker and W. M. Beeson Department of Animal Science
Proteins are a class of nutrients vitally important to the pig. Nutritionally, it is more correct to say that the pig has certain amino acid requirements (the component parts of protein); yet as long as protein sources are used to supply these amino acids, we will probably continue to use the term "percent of protein" as one measure of a ration’s nutritional value.
Extensive research has been conducted at Purdue University for more than 10 years on the amino acid requirements of the growing pig. However, no recent experiments have been conducted at this station to study the protein requirement of pigs from weaning to market or to study certain additives or nutrients which may tend to affect this protein requirement. The National Research Council publication 648 on the Nutrient Requirements of Swine has listed the percent protein required by different weight growing and finishing pigs as follows:	25-pound pig, 17 percent
crude protein; 50-pound pig, 15 percent; 100-pound pig, 13 percent; 150-pound pig,
12 percent; 200-pound pig, 12 percent.
During the past three years, research at Purdue has shown arsanilic acid to be an effective feed additive for stimulating gains and improving feed efficiency of growing-finishing swine (Mimeos 214, 238, and 263). Minnesota researchers 2/ reported that 60 grams of arsanilic acid per ton of mixed ration increased feed efficiency approximately 4 percent but did not appear to have a "protein-sparing" effect under their experimental conditions.
The objectives of this experiment were (l) to study the effect of arsanilic acid on the protein requirement of the growing-finishing pig and (2) to study the effect of three different protein levels (16-13, 14-11 and 12-9) on rate of gain, feed efficiency and carcass quality of growing-finishing swine.
Experimental Procedure
\ Sixty-six Duroc weanling pigs averaging 34 pounds were divided to six lots of 11 pigs each on the basis of sex, weight, litter and general appearance. Each lot was confined to a 30 foot by 40 foot concrete paved lot and fed a fortified corn-soybean meal ration as outlined in tables 1 and 2. One level of protein was fed from 34 to 100 pounds, then this was reduced three percentage units by substituting corn for soybean meal (lots 1 and 2--12 percent then 9 percent. The lower protein rations was fed from 100 to 200 pounds Arsanilic acid (90 grams per ton) was fed in lots 2, 4 and 6. Vitamin and trace mineral additions remained constant throughout this experiment. As each pig reaches market weight, it will be slaughtered and complete carcass measurements collected.
i7 The research reported in this mimeograph was supported in part by grants-in-aid from Abbott Laboratories, North Chicago, Illinois.
2/ Hanson, L. E., Ferrin, E. F. and Singh S.N., 1955. "The Influence of Arsanilic Acid on Protein Requirements of Growing Pigs." J. Animal Science, 14:525.