It is generally assumed that feeding a higher energy density diet will enhance the production of laying hens. The only outstanding question in most people's minds is at what point the higher cost of the high energy diet exceeds the value of improved animal performance.
The key issue in this experiment was the ME content of hen diets, and how manipulation of this affects their egg production and weight. This issue is significant because egg production is one of the most important biological processes in hens.
[...] Energy Intake The metabolizable energy intake of hens on the low energy diet was significantly greater than the ME intake of the control group 0.0190 See Fig The very low energy group showed a trend toward being lower than the control group for ME intake 0.0991 DISCUSSION The objective of this experiment was to determine the minimum dietary energy requirement for body maintenance and egg production in laying hens through manipulation of metabolizable energy content of the hens' diet. We wanted to know how decreasing the metabolizable energy available in the diet would affect the hens' weight, number and weight of eggs, and/or GE per egg. [...]
[...] MATERIALS AND METHODS Subjects Forty single-comb White Leghorn laying hens (female) at 19 weeks of age were used in this experiment. Environmental Conditions The hens were housed individually in cages 1' wide X 1' high X deep with ventilation sufficient to prevent the buildup of ammonia. Each cage included a perch to allow the hens to rest in a natural posture. Temperature was set at 21 C with a 14:10 cycle. The hens were provided with a constant supply of clean water employed through a nipple. [...]
[...] Speculation as to the cause of this gradual decrease in aeration suggests it might be due to the combination of the hen pecking at the food, pushing it down, and simply the exertion of gravity on the food particles. A possible solution to the dry diet could have been to add more water, making it easier to mix. Another alternative could have been to mix one large batch of diet in a mixer rather than individual batches per chicken. This would have ensured more consistent diets across the board for all of the hens. [...]
[...] If more of these hens were in the low energy group (perhaps because their diet was the least palatable and they wanted to eat other food), then this may explain why this group showed a trend towards a lower ME intake. Human-Avian Interaction One factor to keep in mind is that the dietary assignment of the hens was randomly distributed throughout the hen feeding room (i.e. certain diets weren't concentrated in defined locations within the room). This is an important factor to consider because the room contained high and low traffic areas, which caused varying levels of human interaction with the birds. [...]
[...] Egg Production Hens on diet 3(VLE) produced a significantly lower total number of eggs than hens on the standard commercial diet 0.0101 See Fig in the appendix for a graphical representation. Fig shows that the total wet weight of eggs produced by each hen was significantly less for the hens on diet 3 0.00113 There was no significant difference of wet weight per egg between the low energy and control groups. The very low energy group showed a trend in terms of their eggs weighing less than that of the control group 0.0642 See Fig Egg Energy According to the data displayed in Fig.3, the low energy group showed a significantly greater GE content per gram of egg when compared to that of the control group 0.0300 The very low energy group, however, showed no significant difference. [...]
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