The influence of saline drinking water on the activity of carbonic anhydrase in the shell gland of laying hens

1989 ◽  
Vol 40 (5) ◽  
pp. 1111 ◽  
Author(s):  
I Yoselewitz ◽  
D Balnave

Carbonic anhydrase activity was measured in three experiments using mucosal extracts from the shell gland of laying hens given drinking water consisting of town water with or without the addition of sodium chloride (2 g/l). Hens laying eggs with normal or defective shells on both treatments were used. The specific activity of carbonic anhydrase was significantly lower in hens receiving the saline drinking water, but egg shell type had no significant effect on enzyme activity. The results indicate that a reduced activity of carbonic anhydrase in the shell gland contributes to the poor egg shell quality observed in hens receiving saline drinking water.

1989 ◽  
Vol 61 (1) ◽  
pp. 35-43 ◽  
Author(s):  
D. Balnave ◽  
I. Yoselewitz ◽  
R. J. Dixon

1. Supplementing the drinking water of laying hens with 600 or 2000 mg sodium chloride/l induced large increases in egg-shell defects without corresponding changes in egg production, egg weight or food and water intakes. A supplement of 2000 mg NaCl/l resulted in a high incidence of shell-less eggs.2. The increased incidence of egg-shell damage in hens receiving the NaCl was associated with a decrease in egg-shell quality measured objectively. These responses persisted even after the NaCl was removed from the drinking water.3. The NaCl treatment had little effect on blood acid-base balance and electrolytes, but significant reductions were observed in the carbon dioxide tension, and bicarbonate and calcium concentrations in the fluid surrounding the egg in the shell gland.4. The poor shell quality appeared to be associated with a reduced supply of bicarbonate, rather than with an effect on Ca, in the lumen of the shell gland, although a reduced residence time of eggs in the shell gland may also have contributed to the problem.


1993 ◽  
Vol 49 (2) ◽  
pp. 109-119 ◽  
Author(s):  
D. Balnave

Many studies have shown that saline drinking water supplied to mature laying hens at concentrations similar to those found in underground bore water has an adverse effect on eggshell quality and on the incidence of eggshell defects. This response can be observed in the absence of any adverse effects on production parameters such as food intake, egg production and egg weight. Strain differences appear to exist, and even within a strain there is considerable variation in the responses of individual hens to saline drinking water. The sensitivity of the hen also increases with age with a greater occurrence of broken and shell-less eggs. The incidence of shell-less eggs also increases with higher concentrations of NaC1 in the water. The use of saline drinking water with breeder flocks significantly reduces the production of day-old chicks through reduced numbers of settable eggs and lower hatchability. The primary metabolic lesion associated with the poor eggshell quality which results from the intake of saline drinking water appears to be related to the supply of bicarbonate rather than calcium to the lumen of the shell gland for eggshell formation. A reduced activity of carbonic anhydrase in the shell gland mucosa is of particular importance. This limits the supply of bicarbonate and the dependent calcium to the lumen of the shell gland. Treatments which have been found to be effective are preventive rather than remedial in nature. The two most promising treatments, apart from desalination of drinking water, appear to be the use of ascorbic acid supplements in the diet or drinking water appear to be the use of ascorbic acid supplements in the diet or drinking water and the use of zinc–methionine supplements in the diet. The mechanism by which ascorbic acid exerts its effect is unknown but the response is dose-dependent. The zinc component of zinc–methionine appears to be the important factor with this treatment, perhaps through its effect on carbonic anhydrase, a zinc-requiring enzyme.


1992 ◽  
Vol 33 (4) ◽  
pp. 781-794 ◽  
Author(s):  
J. Grizzle ◽  
M. Iheanacho ◽  
A. Saxton ◽  
J. Broaden

2018 ◽  
Vol 98 (4) ◽  
pp. 619-630 ◽  
Author(s):  
D. Kumar ◽  
C. Raginski ◽  
K. Schwean-Lardner ◽  
H.L. Classen

Ideally balanced dietary protein is critical for laying hen egg production and feed efficiency, but also affects other important characteristics. This research was designed to study the nonegg production and feed intake response of Lohmann-LSL Lite hens to 550, 625, 700, 775, and 850 mg d−1 of amino acid balanced digestible lysine (Dlys) from 27 to 66 wk of age. Data collection included hen weight (HW), feather scoring, tissue weights, egg specific gravity, egg component weights, and excreta nitrogen (N) content. The experiment was a completely randomized design and level of significance was fixed at P ≤ 0.05. Hen weight (quadratic, Q), pectoralis muscle (absolute, % – Q), and abdominal fat (absolute – linear, L; % – Q) increased with increasing Dlys intake. Although gastrointestinal segment weights and lengths were affected by Dlys intake, interpretation of results was confounded by other aspects of diet composition. Hen feather score (L) and excreta N content (Q) increased, and egg shell quality (L) decreased with increasing Dlys intake. Absolute egg component weights increased with Dlys intake, but effects on proportional weights were Q and relatively minor. In conclusion, balanced Dlys intake affected a variety of practical nonproduction characteristics in laying hens.


2019 ◽  
Vol 41 (1) ◽  
pp. 42926
Author(s):  
Aliasghar Saki ◽  
Abbas Rahmani ◽  
Azam Yousefi

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