FEEDING OF IODINE TO POULTRY.

New Zealand Journal of Agriculture, Volume XL, Issue 6, 20 June 1930, Page 403

FEEDING OF IODINE TO POULTRY.

SOME LOCAL EXPERIMENTS AND RESULTS.

B. W. Simpson and R. Strand,

Chemical Laboratory,' Department of Agriculture,

Wellington.

It has been shown experimentally that the addition of iodine to the food or drinking-water of fowls will add at. least one year to the productive life of each hen. Not only so, but it has been reported from British Columbia that in certain cases hen-eggs, though fertilized, failed to hatch out; when iodine was introduced into the diet the trouble was removed. The administration of iodine to laying hens also results in an increased iodine content of the eggs, making iodized eggs a valuable food item for those who cannot take iodine in the usual way. The experiments recorded in the following matter were carried out in the Hutt Valley, near Wellington. Some White Leghorn fowls, about four or five years old, were fed potassium iodide in increasing doses in the drinking-water through the spring and summer of -1929-30. In their second and third years these birds had been good layers. Before starting iodine feeding they were moulting and not'laying at all, but after iodine feeding was commenced they laid more eggs than was expected of hens of that age. They also appeared to be healthier, moulted completely, and quickly regrew their feathers. Eggs were collected from these hens, incubated, and hatched out. All the eggs were fertile, and 85 per cent, were pullets. /

There were nine hens. The potassium iodide was weighed out for them and put in the drinking-water trough. The dose was 2 milligrams of potassium iodide per hen per day, but of course they did not all drink the same amount of water. The hens had this dose for three weeks from Ist June. The dose was then doubled, and the hens received 4 milligrams of potassium iodide each per day up to 21st August, 1929.

The results are shown in the following table. In each case the eggs were weighed without the shells.

Normal (non-iodized) eggs from the same place gave the following iodine content: —

lodine feeding was continued from 21/8/29 to 9/10/29, each fowl getting 8 milligrams of potassium iodide in the drinking-water per day, with the following result': —

The iodine was now stopped and no iodine fed for a fortnight previous to 3/11/29. The result is shown in the following analysis :

From 3/11/29 to 18/12/29 the hens were getting approximately 16 milligrams of potassium iodide each per day, from 18/12/29 to 22/2/30 64 milligrams, and from 22/2/30 to 29/3/30 128 milligrams. The hens were killed in the beginning of April. For a few days previous they were getting 256 milligrams of the iodide per day, this being approximately 3 grains of iodine. Three grains is the dose quoted as being the optimum.. One egg was found in the oviduct of one of the hens after it was killed. Table 3 (opposite page) gives the further results.

• Kerens and Roberts {Journal of Hygiene, Vol. 16, No. 1, 30th March, 1927) by a similar experiment increased the iodine content of eggs from 4 gammas to 880 gammas per 100 grammes in a fortnight. Three weeks after the discontinuance of the treatment the iodine content dropped to 14 gammas per 100 grammes.

The iodized hens were killed and weighed. The thyroid glands were dissected out and weighed, and the iodine content estimated. Two normal hens were treated similarly. Two pullets six months old hatched from iodized eggs were also killed, weighed, and the thyroids dissected out and the iodine content estimated. Two normal pullets were treated similarly. Table 4 sets out the results.

■ Fowl thyroids in the United States have been shown to have an iodine content of from 0-105 to 0-38 per cent., and in Scotland from 0-14 to o-2i per cent. Quoting from the literature on this subject, the iodine content of eggs varies- in Switzer land from 8 to 22 gammas per 100 grammes, in Germany from 5 to 33 gammas, in Scotland from 5 to 20 gammas, and in New Zealand from 6 to 14 gammas (Hercus and Roberts). ' Hercus and Roberts also found a distinct seasonal variation : in. the iodine content of eggs, the maximum being in the summer. Some eggs from Tai Tapu, Canterbury, gave on analysis the figures for iodine set out in. Table 5 (next page). It will be noticed that the lowest iodine content occurs in April and May. ... ' ,

General Remarks.

The peculiar point which emerges from the locally conducted iodinefeeding experiments is that the iodizing of the eggs did not have much effect on the iodine content of the thyroids of the pullets hatched from these eggs. They were the smallest thyroids and had the lowest iodine content of all. As previously mentioned, all the eggs from the iodized hens were fertile, and 85 per cent, were pullets.

These experiments confirm the fact that the iodine content of eggs may be increased by a very simple and cheap means, and this affords another method of feeding iodine to the human consumer —a method which may have distinct advantages over others.

* Gamma one-millionth of a gramme.

* Normal egg—no potassium iodide fed.

* Christchurch eggs.

Date. Weight of Egg. ■ . Iodine in Egg.' Iodine in 1 do Grammes Grammes. Gammas.* Gammas.* 3/7/29 50-4 568 1,127 28/7/29 52-6 212 404 21/8/29 Grammes. 50’4 . 52-6 52-2 Gammas.* 568 212 r.r- 213 Gammas.* 1,127 ’ 404 407

Table 1.

Date. Weight of Egg. Iodine in Egg. Iodine in 100. Grammes Grammes. Gammas. Gammas. 1/7/29 Grammes. Gammas. Gammas. 45’4 6 14 29/7/29 53'8 1 8 14 23/8/29 48-9 13 26

Table 2.

Date. Weight of Egg. Iodine in Egg. w Iodine in 100 Grammes 9/10/29 Grammes. .^6-6. Gammas. 425Gammas. 754

Date. Weight of Egg. Iodine in Egg. Iodine in 100 Grammes. , Grammes. Gammas. Gammas.. . 12/10/29 Grammes. 52-2 Gammas. 14 Gammas. 26

A normal egg for comparison gave-

Date. Weight of Egg. | Iodine in Egg. Iodine in 100 Grammes Grammes. Gammas. Gammas. 5/3:1/29 1 Grammes. 1 53-o 1 1 Gammas. 43 Gammas. 80 '

Date. ■ Weight of Egg. Iodine in Egg. Iodine in 100 Grammes. Dose of Potassium Iodide per Hen per Day. Grammes. Gammas. Gammas. 18/12/29 . 54'0 . 520 . 964 16 milligrams. 22/2/30 51'4 1,105 2,150 64 milligrams. 22/2/30 49'3 IO 19 * 26/3/30 .55-3 807 1,461 128 milligrams. 29/3/3 0 42-6 1,057 2,483 128 milligrams. 29/3/30 . 58-i 956 645 128 milligrams. 23/3/30 44'7 •12 - 26 * 27/3/30 44-9 l6 36 ❖ 2/4/30 37'9 . 2,231 5,887 . 256 milligrams (egg from oviduct).

Table 3.

Date. Description. Weight of Hen. Age of Hen. Weight of Thyroid. Iodine in Thyroid. Percentage of Iodine. ■ Weight of Hen. Age of Hen. Weight of Thyroid... Iodine in Thyroid. Percentage of Iodine. lb. oz. Grammes, Grammes. 2/4/30 Iodized hen laying ... 4 I 3 years .. 0-1380 0-007 O-.5O5 ■ ■ 2/4/30 Iodized hen just stopped laying 3 IO 4 years 0-2655 o-ooii o426 2/4/30 Iodized hen not laying 3 142 .5. years... 0-2049 0-0004 0-212 2/4/30 Iodized hen not laying 4 IO 5 years 0-2571 . 0-0004 0-147 2/4/30 Non-iodized hen 2 14 3 years 0-1766 0-0004 0-217 7/5/30 Non-iodized hen • ’. 3 11 3 years ' 0-2408 .0-6004. O.-I54 T 2/4/30 Pullet from iodized egg 3 2 6 months 0-1140 o-oooi 0-097 2/4/30 Pullet from iodized egg 2 12 6 months 0-0830 O-OOOO6 0-067 . 2/4/30 Pullet from non-iodized egg 2 0 6 months 0-1197 O-OOO2 0-178 ■ 14/5/30 Pullet from non-iodized egg 2 15 6 months 0-1297 0-0002 0-138

Table 4.

Date. • Weight of Egg. Iodine in Egg. Iodine in 100 Grammes 21/9/29 Grammes. 43’8 Gammas. 9 Gammas. 19 24/10/29 53’0 7 14 IT / XI/IQ 42-7 8 19 31/1/30 47-8 ■ ' 7 14 24/2/30 53’2 10 18 24/2/30 48-5 9 19 3/4/30 65-4 5 8 3/5/30 ■ 56-1 5 10 21/9/29* 47-6 7 14 21/9/29* 42-2 10 25

Table 5.