Experimenting with poultry nutrition

Valuable research work that has been going on at the University of British Columba for the last several season, was reviewed at a meeting of the Vancouver Poultry Association in April by Dr. V.S Asmundson, who gave a most instructive talk to the members on “Nutrition”.  On this page we present some of the conclusions that have been arrived at.  Every poultryman will be interest in this subject for upon his ability to feed properly will largely depend his success in maintaining his flock at the highest point of health and profit – Editor.

Growth and development play a very important part in agriculture.  It is only necessary to refer to broiler production to indicate the important relation between growth and profits in the poultry industry.  Since it is necessary to grow a new crop of pullets every year all poultry producers are vitally interested in growing the young stock economically.

It may be worthwhile to refer briefly to the inheritance of rate of growth.  The various breeds differ in rate of growth, and these differences are inherited.  There are also variations in the rate of growth of birds of the same breeds and these differences have likewise, been demonstrated to be inherited.  Rate of growth can, therefore be increased by breeding only from the more rapidly growing birds.

Both cattlemen and poultrymen, in order to meet market demands, have found it necessary to breed and feed for rapid and ever more rapid growth.  They want their stock to reach the market or maturity in as short a time as possible.  Years ago, breeders and feeders took more time and were content with a slower development, thus the problems that confront us today in many cases did not exist formerly.

Failure to provide adequate room and correct heat is the cause of much of the retarded development in feathering and body growth.

Chickens must be supplied with all the necessary nutrients; especially is this important when chickens are raised in confinement and are, therefore, unable to supplement deficiencies in their ration by selecting foods containing vital minerals that are available to them when on a good rangd.

Experiments with fishmeal

Experiment were started in 1928 to determine the value for growth of different B.C. fish meals.  In the first experiment, Lot 1 was fed a ration containing 76.6 cornmeal, 2.9 bone meal, 2 oyster shell, 1 salt, 2 cod liver oil and 15.5 pilchard meal.  At eight weeks the chicks had attained an average weight of only .7 lb.  In this case it will be noted that corn was the only cereal included in the ration.  In a later lot (Lot 2) fed fro the same length of time on a ration containing approximately the same percentage of pilchard meal but made up of 50 lbs. cornmeal, 10 lbs. wheat bran, 10 lbs. middlings, 10 lbs. pulverized oats, 3 lbs. oyster shell, 1 lb. salt, 1 lb. fish oil and 15 lbs. pilchard meal, the chicks grew better. Their average weight at eight weeks varied from 1.2 to 1.5 lbs.  This demonstrates that the rate at which chicks grow depends not only on the animal protein feeds such as fish meal, meat meal or mil, but also on the feeds with which they are mixed (grains and their by-products, minerals, etc.). It is desirable to use a variety of grains or grain products.

In order to compare different fishmeal and dried skim mild, each was fed in such amount as to supply the ration with 10 per cent of protein from the particular supplement used.  The amount (in 100 lbs. of the rations) and kind of supplement feed was as follows:

19 lbs. salmon meal (55 per cent protein); 15 lbs. pilchard meal (65 per cent protein); 19.4 lbs. halibut meal (54 per cent protein); 27.2 lbs. dried skim milk (35 per cent protein).  The basal to which, these animal protein feeds were added was the same as given above (50 lbs. cornmeal, 10 lbs. wheat bran, 10 lbs. wheat middlings, 10 lbs. pulverized oats, 3 lbs. oyster shell, 1 lb. salt and 1 per cent cod liver oil).

In some of the earlier experiments 3 lbs. of bone meal was fed instead of the 3 lbs. of bone meal was fed instead of the 3 lbs. of oyster shell.  A considerable number of the chicks fed bone meal developed enlarged hocks or “slipped tendons.”  After oyster shell was substituted fro bone meal very few cases of slipped tendons were observed.

Two experiments were carried out at the University using the fishmeals and milk in the proportions stated above.  In the first experiment the results were as follows:

Halibut, average weight of chicks at 8 weeks, 1.32 lbs.; Salmon, average weight of chicks at 8 weeks, 1.42 lbs.; Pilchard, average weight of chicks at 8 weeks, 1.46 lbs.; Milk, average weight of chicks at 8 weeks, 1.49 lbs.  Similar results were obtained in the second experiment.

These experiment showed that chicks can be grown as rapidly on fish meals as they can be grown on dried skim milk.  The next series of experiments was, therefore, planned to determine whether a combination of fishmeal (salmon) and dried skim milk would give as good or better results (in rate of growth) than could be obtained by feeding these supplements singly.  Three protein levels were compared.  In one the supplements (salmon or salmon and milk) provide 10 per cent protein, in the others, 7-1/2 and 5 per cent respectively.  The milk and salmon supplied an equal amount of protein in the rations containing both.  Since the milk contains a lower percentage of protein than salmon this meant that more milk than fishmeal was fed. The results of these experiments were as follows.  The chicks on the 10 per cent protein level (from supplements) made better gains on the salmon and milk than on salmon only.  The chicks that received 7-1/2 per cent protein from the combined supplements grew more rapidly than those fed salmon only but did not grow quite so fast as the corresponding groups on the 10 per cent level.  There was no difference on the lowest protein level (5 per cent from supplements) between the chicks, which were fed salmon as compared with those, which were fed salmon and dried skim milk.

In these experiments there was no difference between the weights at eight weeks of chicks receiving 10 or 7-1/2 per cent protein from salmon alone. The chicks fed salmon and milk to provide 10 per cent protein (from these supplements) grew more rapidly than those on the 7-1/2 per cent level but the difference was not great.  The chicks on the lowest protein rations grew more slowly, in every case, than the checks on the higher protein levels, and there was no difference between those feed salmon only as compared with toe fed salmon and milk.

Since the proportion of milk fed in the experiments just described was rather high, the next step was to test the effect of various proportions of fish meal and dried skim milk on the growth of chicks to eight weeks of age.  These experiments indicate that rations containing 5 per cent of dried skim milk and 10 per cent of a high-grade fishmeal will give just as rapid growth as rations containing more milk.  The results vary slightly according to the kind and quality of fish meal used.

Variation in Fish Meals

There are some variations in the quality of different fish meals even if they are made from the same kind or species of fish.  Some work done on fish meals at the Dominion Fisheries Experimental station of the Biological Board at Prince Rupert shows that putrefaction destroys some of the essential amino-acids.  Meals made from such putrid fish are not toxic but are probably lower in feeding value than meals made from fresh fish. Putrid fish is, of course, generally made into fertilizer and not into meal.

As an example of the variation in fish meals, two trials with pilchard fish meal may be mentioned.  Four meals were compared.  All four meals proved satisfactory as measured by rate of growth, yet one of these meals was definitely superior to at least one of the other meals while the other two appeared to be intermediate.  The best meal was lowest, the poorest meal highest, in fat content.  Slight variations in the protein and mineral content apparently had no influence, in this case, on the rate of growth.  These experiments indicate that the best pilchard meals are those with the lowest fat content.  They emphasize the importance of buying meals of good quality.  This should not be difficult since there is not plenty of high-grade fish meal on the market.

The work with fish meals has opened up a number of problems of interest alike to the feeder and the manufacturer of fish meal.  Of particular importance is the variation in the quality of fish meals and the reasons for such variations.

Fish oils for chicks

In any discussion of chick rations the question of the relative merits of different fish oils should be considered.  Cod liver oil has been used for many years as a source of vitamin A and D, particularly the latter.  This oil varies in vitamin potency depending on where the fish are caught and the season or time of year.  The main fishing banks are off Newfoundland, Norway and Iceland.  In general the Newfoundland oil is richer in vitamin D but this is not always true.

In recent years other oils have been tested with the object of using them in poultry rations.  The oil made from pilchard, or sardine as this fish is called in California, has been found satisfactory for poultry feeding.  In the test at the University of British Columbia cleared and uncleared B.C. pilchard oil, California sardine oil and cod liver oil all gave equally good results when fed at a level of 1 per cent.  The chicks that were not fed oil developed rickets at less than four weeks of age.  These oils were not tested for vitamin A but work done elsewhere shows that pilchard oil contains this vitamin.  It should be emphasized that fish oils are purchased for their vitamin D content rather than their vitamin A.  Vitamin A can be obtained more cheaply from other sources such as alfalfa leaves and blossoms.  Yellow corn also contains this vitamin.  As is well known, sunlight is the cheapest source of vitamin D.  Birds confined indoors should be fed fish oils as a substitute for sunlight but, since these oils vary in vitamin potency, only tested oils should be purchase for poultry feeding.