from components fed in the hen’s diet, meaning optimum gut health ensures optimal shell quality. Likewise, a poor-quality diet is likely to lead to a poor-quality shell. Gen- erally, an egg is produced daily. To maintain production, the hen must be able to digest and absorb all of the energy and nutrients she needs from her diet. Egg formation is a complex and energy-rich process. The yolk passes out of the ovary through the reproductive system. Each step — be that albu- men formation or shell formation — requires specific miner- als and nutrients. Hens must have all of their nutritional needs met, but some minerals are vital. Zinc (Zn) is a good ex- ample. Not only does it perform functions in the cells of the immune system, but it works as a co-factor for an enzyme in- volved in the production of CaCO3


. Not enough Zn can lead to


weak shells. Manganese (Mn) activates an enzyme involved in the production of glycoproteins and glycosaminoglycans, which constitute 2–4% of the eggshell through their roles in the organic matrix. Copper (Cu) is involved in the formation of collagen, the part of the eggshell membrane surrounding the yolk and albumen and the layer on which the shell is laid. Selenium (Se) is crucial as a natural antioxidant, but also in the egg itself, and has a big impact on maintaining freshness.


Critical minerals Without a healthy gut, birds cannot absorb critical minerals efficiently. This, alongside mineral form, hugely influences mineral bioavailability; organic chelated minerals are better absorbed than their inorganic counterparts for this reason. When producers focus on their flock’s gut health by using products like Actigen, it allows the bird to produce the best structural integrity within their gut. Healthy villi will have a large surface area, with good crypt depth: villi height ratios. Gut health and the microbiota directly impact villi structure and integrity. So, optimal health ensures that nutrients can be effectively absorbed across the epithelium into the blood- stream or lymph. In subclinical disease challenges or when gut health is not optimal, surface area will be hugely reduced, and villi structure impacted. As well as impacting digestion and absorption, inflammation is also likely if the microbiota profile is not correct. This provides an extra mucus barrier through which nutrients, including minerals, must pass be- fore being absorbed, influencing shell quality and strength. If gut health can be improved, the negative consequences as- sociated with increased inflammation and insufficient nutri- ent uptake can be avoided. Shell strength depends hugely on the structure of the internal shell components. Studies show that where structural integrity is compromised, shell strength suffers. Minerals play a vital role in ensuring that mechanical structures can be deposited correctly, either directly through their use in complexes or through their use as co-factors in enzymes involved in the manufacturing process. Compro- mised gut health affects mineral uptake, which can reduce shell strength. It is important to consider the type of minerals


utilised in diets, as this too can impact shell strength through bioavailability differences. Organic che- lated minerals have superior up- take when compared to their inorganic counterparts and interact less with vitamins when in the gas- trointestinal tract. The type of chelate will also impact stabili- ty and interaction and, hence, bioavailability. So, careful se- lection for diets should be made.


Microbiota profile Gut health also significantly impacts litter quality. Whatever is not digested and absorbed, will be defecated into the litter. If the microbiota profile in the gut can be improved, the house flora will improve too, decreasing disease pressure. The most noticeable indicator of gut health in a laying bird is the colour and texture of her faeces. Caecal droppings are especially clear indicators of microbiota population health. Monitoring them is an easy way for producers to examine flock health. Dark green droppings with a pasty consistency are ideal, whereas yellow and foamy droppings indicate possible is- sues. Alltech’s Online Manure Scoring System is a new tool for monitoring and advising on gut health status within flocks. As birds age, they produce larger eggs with changing mineral requirements. Gut health will remain as the limiting factor to performance and egg quality, so optimisation is key to achieving peak performance and profitability. Due to COV- ID-19, with people spending more time at home, baking and cooking, egg demand has sky-rocketed. This has been good for the egg market in terms of an upturn in growth. Even when returning to a sense of normality, demand is expected to remain high. With this in mind, first-class eggs become a priority. Shell strength should be a focal point when aiming for better downgrade levels, and this is possible by looking at the mineral form. However, the importance of a good quality diet and gut health should also not be overlooked.


▶ GUT HEALTH | DECEMBER 2020 43


Shell strength depends hugely on the structure of the internal shell compo- nents.


PHOTO: DREAMSTIME


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