Symptoms and Control of X Chick Disease

New Zealand Journal of Agriculture, Volume 87, Issue 3, 15 September 1953, Page 269

Symptoms and Control of X Chick Disease

THE condition X chick disease has become ■ quite well known to poultry farmers in many areas of. the South Island, and the name, originally given because of its unknown cause, has continued in popular use. After several seasons of field investigation and experimental work the disease is recognised as a form of vitamin E deficiency. This article by J. J. Thompson, Veterinary Research Officer (Poultry), Department of Agriculture, Wellington, describes briefly the research work carried out. and the results which have been obtained together with recommendations on the prevention of chick losses from the disease. Alarming losses of up to 80 per cent, in batches of young chicks on poultry farms in the Dunedin and Invercargill areas were reported during the 1950 rearing season. Early attempts at diagnosis soon showed that a new condition was being encountered. From the number of birds affected and the apparent rapid spread of the disease it was obvious that the condition was: — 1. An infectious disease probably, of bacterial origin; or 2. A condition caused by some factor common to all the chicks, such as a fault in management or a nutritional deficiency which would affect the whole batch of chicks. The cause of the condition remained unsolved during that season, and further research work had to be postponed until the following year to await any fresh outbreaks which might occur. In the meantime a limited survey showed that the disease had occurred fairly extensively throughout the area.

In the following year the disease was encountered in the Canterbury, Otago, Southland, and West Coast areas. Ample material was therefore available for laboratory examination, and full advantage of it was taken to follow up the work done in the previous season. Full reports of the disease, the management conditions, the source and type of feed used, the symptoms and death-rate, and all the

details which might furnish even a little extra information were sought from the affected farms. In this way a comprehensive knowledge of X chick disease was ' built up and recorded for study. The facts obtained showed that the disease was present on poultry farms which reared chicks by battery brooders, by infra-red lamps, by electric hovers of various types, and under conditions, of management which ranged from very good to very poor. This information ruled out the possibility of the. condition being caused by bad management. In addition all attempts to transmit the disease from affected to healthy chicks failed, both in the field and in the laboratory, and extensive laboratory work to isolate bacteria which could be responsible was equally unsuccessful. Full consideration of the facts obtained from field investigations and the symptoms and course of the disease combined with the failure to show that the disease was infectious pointed to the condition being a nutritional one. In the symptoms and post-mortem lesions of the disease some resemblance was noted to an experimental condition which arose from the feeding of a particular artificial diet to chicks and which proved to be a form of vitamin E deficiency. This experimental condition, known as exudative diathesis, could be prevented by adding vitamin E to the diet either in the form ■ of the pure vitamin or of a foodstuff containing it, such ; as wheat germ meal, This opened a new line of investigation, subsequently proved to be the right , one.

Symptoms The early signs of the condition are usually observed between the third and fourth weeks, especially around the twenty-first or twenty-second day, and the train of symptoms is fairly constant. - At . first there is a fairly sudden general loss of condition followed: by evidence of leg. weakness in individual chicks, which move around with a stiff, stilted gait. Leg weakness develops into inability to stand upright and a tendency to huddle in a . corner or ; . under the. source of heat., A number of deaths may occur at this stage, ; A swelling on the breast which extends along the wings and down the abdomen and legs and is due to fluid collecting under the skin may occur. The swollen area • usually appears. greenish blue or purple. In some outbreaks the appearance of a swelling at. the back of the head has been a prominent feature. ‘ This may also,. be. observed in survivors, at the age - of 8 to. 9 weeks. It has been reported .that release of . the fluid under the. skin by incising the swollen part often leads to the recovery of the chick. Post-mortem Report - When a fresh carcass was opened the fluid under the skin was immediately obvious from the glistening wet appearance. Usually it was coagulated to form a jelly-like covering of the muscles of the breast and abdomen, . which varied from yellow to a dark blue. T- : Tiny hemorrhages were usually prominent on the muscle surface, and the fat tissues ■ appeared abnormal.Small, grey-white streaks - -on ■ the muscle - ;: were - evident, indicating severely -damaged, or dead musclefibres. -..- .

Experimental Work To ascertain the correctness of the assumption that X chick disease was similar to the vitamin E deficiency condition known as exudative diathesis some trial treatments of affected birds were necessary. A batch of chicks 24 days old showing early signs of the disease was

transported by air to the Department of Agriculture’s Animal Research Station, Wallaceville. Special arrangements for dispatch and reception cut down delay on the journey, and the birds appeared to be none the worse for the trip. Two birds died shortly after arrival, and post-mortem examination confirmed the cause of death as X chick disease. Of the survivors at least 30 per cent, showed typical symptoms of the condition. A supply of the mash and grain used during the rearing of the chicks was also received. Trial No. I The birds were divided into 3 groups and placed in battery brooders to try the effect of vitamin E against X chick disease. The three groups were fed on the same diet as they had been receiving since the day old stage. The birds in group 1 were dosed with pure vitamin E (dl alpha tocopherol), those in group 2 were the controls and received no special treatment, and those in group 3 were fed aureomycin mixed with the mash. The aureomycin was included because of a report that it had been successfully used to treat the disease on one farm. The result of this trial is shown in the following table: —

As the numbers of birds in the groups were not equal, the percentage death-rates give a clearer picture of the results. .. The only death in the group treated, with vitamin E was a bird which was very badly affected before the trial started and which died., on the second day.

Apart ' from the difference in mortality, the appearance of the treated birds in group 1 was greatly superior to that of the untreated birds (group 2). (See illustration above.) The birds treated with aureomycin (group 3), showed increased growth and weight, but the death-rate was almost ’ as high as that of the untreated birds. These encouraging results justified a further experiment on the use of vitamin E for prevention and cure of the condition, and a second trial was set up at the Poultry Demonstration Plant, Upper Hutt. Trial No. 2 To obtain further proof that the condition was a nutritional disease an attempt was made to produce the condition in chicks. At the same time one group was fed vitamin E to show that it was of value in protecting against the disease. Two batches of 50 chicks from separate hatches at the Poultry Demonstration Plant were set up in 4 pens containing 25 birds each. Pens 1 and 2 were from the same hatch and pens 3 and 4 were from a later hatch. The diet consisted of standard chick mash No. 1 to which had been added crushed wheat, crushed maize, skimmed milk powder, and cod liver oil. This mash was brought in from a poultry farm severely affected by X

chick disease. It was fed to all four pens, but the chicks in pen No. 4 had pure vitamin E added. Infra-red lamps were used for brooding. The typical symptoms of X chick disease were reproduced, and the number of deaths in each pen are shown in Table 2 below: —

One chick from each batch died before the fourteenth day from other causes. ;; The first symptoms were evident about the twenty-second day in pen 2. From information obtained since it seems highly probable that the deathrate in the treated pen would have been lower if a higher amount of vitamin E had been fed. In both trials it has been shown i i that X chick disease can be preh vented and possibly cured by the ■: administration of vitamin E. .' Cause of Vitamin E Deficiency ? All the evidence shows that the disease is of nutritional origin and is probably a form of vitamin E deficiency. The next problem to be answered is which constituent of the feed is responsible, for producing the

shortage of vitamin E in the diet. The standard diet which contains wheat and other grains plus meat meal, milk powder, and green feed should contain sufficient vitamin E to supply the needs of the growing chick. It appears then that some factor or factors are present in the feed used which prevent the chick making use of the vitamin E actually present in the food, that is, something which has an anti-vitamin E effect. It has been shown experimentally overseas that fish liver oils fed to excess can have this effect, but on many of the farms affected only the normal amount of oil was being fed. An important point is that X chick disease has so far been encountered only in the South Island. The only obvious difference in diet constituents between the North and South Islands is the different source of wheat used. In the North Island most of the wheat is of Australian origin, whereas in the South Island it is largely home grown. The home-grown wheat is usually harvested by combine machines and is frequently cut when wet. The grain is bagged by the machine and dumped on the field until it is convenient to remove and store it. During wet seasons the grain may be left bagged in the field for a considerable period, and sprouting will begin. In a number of samples observed the sprout appeared to have dropped or withered off, leaving a small black spot. The high moisture content may also cause heating during storage, and there is also the possibility that the wheat may be affected by moulds. If this grain contains a substance or factor which affects the vitamin E normally present in poultry feedstuffs, it may offer some explanation of the outbreaks of X chick disease being confined to the South Island. To test this theory another experiment was carried out using a batch of wheat obtained from an Invercargill poultry farmer who had suffered losses from X chick disease. Although the results of this experiment have not yet been fully assessed, the fact that a number of deaths occurred from typical X chick disease in the trial pens lends support to the theory that certain batches of wheat are responsible. Further work remains to be carried out before a positive statement can be made as to the actual role played by the wheat in the production of the disease. The present findings, however, justify the Department of Agriculture advising poultry farmers who have suffered loss from this disease to feed 5 per cent, of wheat germ meal or a mash containing vitamin E in another form such as dl alpha tocopherol. A brief summary of the position therefore is that an unidentified chick disease occurring only in the South Island has been investigated and has proved to be of nutritional origin. The disease can be prevented by supplementing the diet with vitamin E in the form of 5 per cent, of wheat germ meal, or with dl alpha tocopherol (pure vitamin E). The cause of the nutritional deficiency of vitamin E is not yet fully known, but there are good grounds for suspecting that it arises from feeding South Island wheat which has sprouted and overheated because of poor conditions of storage.

Bulletins for the Commercial Poultry Keeper Free Bulletins Nos. 239 Curd Feeding to Poultry. 318 Pullorum Disease. 327 Internal and External Parasites of Poultry. 331 Symptoms and . Control of Fowl Pox. ' 332 Tuberculosis of Poultry. Chargeable Bulletins Nos. . . 197 Theory and Practice of Incubation. 6d. 199 Chick Raising. 6d. .The above bulletins, part of a series of over 350 on all aspects of farming, are available post-free from the nearest office of the Department ■■ of Agriculture, or from the Head -. Office of the Department, Box 2298, ■■ Wellington.

Group No. of chicks Treatment No. of Percentage deaths of deaths of deaths 1 12 Pure vitamin E 1 8.3 8.3 2 18 Controls 9 50.0 50.0 3 II Aureomycin 5 45.5 45.5

TABLE 1

► ■- .. of Percentage Pen Treatment No. of deaths Percentage of deaths i 1 Special diet 14 56 2 Special diet 17 68 3 Special diet 20 80 4 Special diet Special diet plus 20 80 pure vitamin E < 6 24

TABLE 2