A study was conducted to investigate the influence of different particle sizes of a
specific amorphous limestone source (calcium carbonate) in a layer diet on egg
production and egg quality at peak production (week 24).
Ninety nine layer pullets, 17 weeks old, were obtained from a commercial layer
breeder. The pullets were randomly allocated to three groups. All the pullets received
the same layer diet. The only differences among the treatment groups were that the
pullets in each group received one of the three different particle sizes in the diet
namely:-
(a) Less than 1.0 millimetre
(b) 1.0 and 2.0 millimetre
(c) 2.0 and 3.8 millimetre
The influence of the three particle sizes on the feed intake, body weight and egg
production as well as egg characteristics was recorded.
The average weekly feed intake, body weight and egg production of layers from week
18 up to 28 were not (P> 0.05) different among the layer diets with the different
particle sizes. The particle size of limestone in the layer diets did not influence egg
weight (P= 0.2159) and egg output (P=0.2388) significantly at peak production.
Average egg weight tended (P= 0.2159) to be heavier when coarse particles were fed.
No statistic al significant (P> 0.05) differences in egg volume, egg contents, egg
surface area, shell weight per unit surface area, shell percentage and shell thickness
occurred. According to these results limestone particle size in layer diets has no
influence on eggshell quality.
In the second study the effect of particle size distribution of a specific limestone
source in layer diet on egg production and egg quality at peak production (week 24)
was investigated. One hundred and sixty seven layer pullets , 17 weeks old, were obtained from a
commercial layer breeder. The pullets were randomly allocated to five groups. All the
pullets received the same layer diet. The only differences among the treatment groups
were that the pullets in each group received one of five different ratios of fine (less
than 1.0 mm) and coarse (between 2.0 and 3.8 mm) limestone particle size namely
100, 75, 50, 25 and 0 % fine or coarse. The influence of the five dietary limestone
particle size distributions on the feed intake, body weight, and egg production of
layers as well as egg characteristics mentioned in the first study were investigated.
No significant (P> 0.05) influence of dietary limestone particle size distribution was
found on feed intake, body weight and egg production of layers. Accordingly no
significant differences occurred in egg volume, (P= 0.1310) and egg surface area (P=
0.1393). The highest (P< 0.001) egg contents were recorded where 100 and 75% fine
limestone particles were included in the diet. Although significant differences for
shell weight (P<0.0017) and shell percentage (P<0.0001) occurred, no clear influence
of particle size distribution on these characteristics could be detected.
In accordance wit h shell weight per unit surface area no significant differences (P>
0.05) in eggshell thickness occurred.
It was concluded that different dietary limestone particle sizes and distributions have
no influence on eggshell quality at peak production (week 24). The influence of
dietary limestone particle size and distribution during the later stages of the laying
period on bone formation and egg quality needs further investigation.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:ufs/oai:etd.uovs.ac.za:etd-09302005-085006 |
| Date | 30 September 2005 |
| Creators | Phirinyane, Boitumelo Tobin |
| Contributors | Prof JP Hayes, Prof HJ van der Merwe, Prof JEJ du Toit |
| Publisher | University of the Free State |
| Source Sets | South African National ETD Portal |
| Language | en-uk |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.uovs.ac.za//theses/available/etd-09302005-085006/restricted/ |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to University Free State or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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