The large scale incubation of fertile eggs in the commercial broiler and layer industry is difficult to manage, particularly keeping an even, ideal temperature for each individual egg. Temperature variation and fluctuation does occur in commercial incubators, and can cause major problems with embryo development and survival.

As one of the most powerful osmolytes in nature, betaine enables microbes, plants and animals alike to be more resistant to osmotic, heat, cold, disease or environmental stresses. It is hypothesised the supplementation of betaine will allow incubated embryos to be more resistant to temperature fluctuations, allowing the bird to perform to its genetic potential.

"If I just take the chicken meat industry as an example, improvements in chick quality and subsequent growth through betaine supplementation has the potential to increase feed efficiency by at least two per cent, which is approximately A$55 million in savings to the industry producing 550 million broilers per year," said project (sub-project 2.1.1) leader, Dr David Cadogan. "For the egg industry, it is possible that an increased betaine level in the egg may enhance the health benefits of eggs."

The pilot study for this project has now been completed. For this initial study, 60 laying hens were divided into two groups of 30 birds and allocated an experimental dietary treatment each. The dietary treatments were sorghum/soy-based and were formulated to meet the birds' nutrient requirements. One treatment was supplemented with 1kg/tonne (1000ppm) betaine and the other served as a control ration (0ppm).

These diets were fed to the laying hens for a period of 42 days (with a 10-day acclimatisation feeding of the experimental diet prior to the start of the trial) during which time weekly egg weights, feed intake and egg quality information was recorded. Collected eggs within treatments were homogenised each week, with a sub-sample freeze dried and sent to Danisco, Finland, for betaine analysis. Analysis was via acetonitrile and methanol extraction, and betaine was determined as bromophenacyl ester derivatives with UV detection by HPLC.

Table 1 outlines betaine content of eggs as analysed by Danisco. The beneficial effect of betaine on laying hen performance was not confirmed in the pilot study.

Dr Cadogan said: "There was no significant effect of treatment on any performance parameter, although there was a numerical 2.4 per cent increase in egg weight."

It was noted that the subject birds were at the end of the laying cycle and had previously been fed on a wheat-based diet, making possible stress effects of a change in diet obscure the treatment effects.

Dr Cadogan added: "The study did, however, demonstrate that the betaine content of the egg can be manipulated by the diet. The addition of 1,000ppm of Betafin S1 increased the betaine content by 0.91mg per 100g. The significant increase in the betaine level of homogenised egg contents suggests there is a high potential to improve embryo survival."