**2. Coccidiosis and nutrition**

From the nutritional standpoint, *E. acervulina* and *E. maxima* are the most influential species because of the strategic anatomical location being in duodenum (affecting the release of pancreatic juices) and jejunum intestine (nutrient absorption) respectively. *E. acervulina* and *E. maxima* significantly reduces the water consumption and feed intake simultaneously during acute coccidiosis, however the ratio of water intake to feed intake did not differ between chicks with coccidiosis and healthy birds. Hence, nutritional deficiencies and impaired nutrient absorption can occur following feed and water intake restrictions [11, 12].

Nutritional factors are key players in several steps of the coccidiosis disease. Firstly, as a susceptibility or protection component, secondly, during the process of infection and pathogenesis, and thirdly, in the recovery and compensatory growth of the bird.

Based on that, there are some facts pointing out that the presence of intestinal lesion scores correlates with decreases in average daily gain (ADG), energy consumption, retained energy and feed efficiency. Increments in maintenance is also reported while also seeing increase in excreted energy as well as reduced digestibility in most of the dietary nutrients [10]. The activation of immune response also occurs and requiring use of nutrients that cannot be addressed to the conversion of nutrients into meat, the key goal of broiler production. Therefore, it is paramount to figure out that any level of *Eimeria* infection is causing an evident, but difficult to estimate, loss in performance.

The use of good quality ingredients would aid in nutrients losses during infection and might help to reduce the potential secondary health issues. Nutrient dense diets during infection may be used to counteract performance losses and to enhance compensatory growth phase.

### **3. Malabsorption of nutrients**

A reduction in apparent ileal digestibility of some nutrients including nitrogen, starch and fats in challenged birds with *Eimeria* has been reported [10]. As expected, coccidia challenged reduced starch, fat, and amino acids (AA)

**163**

of vitamins.

*Nutrition and Poultry Coccidiosis: Causes, Consequences and Current Strategies to Modulate…*

digestibility. Of these nutrients, fat digestibility was recognized as the most affected by the level of intestinal lesion [10]. Besides, an estimation of the intestinal damage and its impact on fat and AA digestibility was done. For each unit of impairment in total lesion score, digestibility was decreased by 16% and 3.8% respectively [10]. The first sign seen in birds which are infected with *Eimeria* is loss of pigmentation. In some countries, the coloring of the skin of broilers is an important factor when consumers choose the bird that they want to buy, as they directly associate yellowness or even goldenness with high quality, freshness, and country chickens [13, 14]. The extra cost for to achieve the level of desired pigmentation is high being between 8 to 10 percent of the total feed cost. Carotenoids are fat soluble and a loss of digestible energy specially of fats also affects its absorption in plasma. Besides, it is absorbed through the ciliary epithelium of the midgut and, for this take properly, a process of enzymatic hydrolysis of the xanthophylls, present in the diet in the form of fatty acid esters, must occur. During coccidia challenges, there is a decreasing up to 88% in serum levels of lutein. Some species of *Eimeria* cause desquamation and shortening of the villi of the intestinal mucosa and infects the sites of

The optimum pH of gastrointestinal tract is crucial for the action of digestive enzymes. However, coccidiosis infection has been responsible of causing malabsorption of nutrients which is related with the alteration of pH and morphological alteration including flattened villi and elongated [16]. The intestinal content was significantly lower in pH in birds after 5–9 days post infection of *E. acervulina, E. mivati, E. maxima, E. necatrix* and *E. brunetti* than in uninoculated control birds causing the impairment in absorption of nutrients [17]. Consequently, *Eimeria*induced pH reductions likely impact nutrient digestion and absorption in the intestinal lumen. Also, pancreatic and mucosal brush border enzyme activity is affected at the tissue of infection, whereas brush border enzyme activity may be altered in uninfected intestinal regions compensating for losses in nutrient recovery [18]. Decreased activities of digestive enzymes located on the upper half of the villi, such as disaccharidases, indicate a damaged brush border with a decreased digestive

**4.** *Eimeria* **infection and protein, amino acids and vitamin dietary levels**

Britton et al. (1964) showed the interaction between dietary protein levels and coccidiosis varying from 0 to 30% in intervals of 5% [20]. They found a significant reduction of mortality rate and in intestinal lesion score with 0 and 5% of dietary

Nutritionists and parasitologists have argued for a long time the relation between coccidiosis and dietary protein levels. Early studies showed that chickens fed with high crude protein levels (between 20.5 to 22%) and high-vitamin A and B diets (40% more vitamin A, and about 20% more vitamin B of the requirements respectively) compared with low-protein (between 14.5 to 15.5%) and low-vitamin diet and exposed to equal numbers of *E. tenella* oocysts, had a consistently lower excretion of oocysts after 5 days of exposure and less than half the peak of oocyst shedding on day 7 post infection. Mortality percentage was 5% in the high-protein and high-vitamin A diet, compared to 23% in the low-protein and low-vitamin A diet. However, on the fifth and sixth day, the results were completely the opposite, suggesting that a high amount of protein and vitamin on the feed are overcoming the damage of acute coccidiosis. Nonetheless, during a chronic state of the disease, high levels of dietary proteins, caused an impairment of birds health [19]. As a shortcoming of this study, the effect of protein was not separated from the effects

*DOI: http://dx.doi.org/10.5772/intechopen.96995*

greatest pigment absorption in the intestine of birds [15].

absorptive capacity [16].

#### *Nutrition and Poultry Coccidiosis: Causes, Consequences and Current Strategies to Modulate… DOI: http://dx.doi.org/10.5772/intechopen.96995*

digestibility. Of these nutrients, fat digestibility was recognized as the most affected by the level of intestinal lesion [10]. Besides, an estimation of the intestinal damage and its impact on fat and AA digestibility was done. For each unit of impairment in total lesion score, digestibility was decreased by 16% and 3.8% respectively [10].

The first sign seen in birds which are infected with *Eimeria* is loss of pigmentation. In some countries, the coloring of the skin of broilers is an important factor when consumers choose the bird that they want to buy, as they directly associate yellowness or even goldenness with high quality, freshness, and country chickens [13, 14]. The extra cost for to achieve the level of desired pigmentation is high being between 8 to 10 percent of the total feed cost. Carotenoids are fat soluble and a loss of digestible energy specially of fats also affects its absorption in plasma. Besides, it is absorbed through the ciliary epithelium of the midgut and, for this take properly, a process of enzymatic hydrolysis of the xanthophylls, present in the diet in the form of fatty acid esters, must occur. During coccidia challenges, there is a decreasing up to 88% in serum levels of lutein. Some species of *Eimeria* cause desquamation and shortening of the villi of the intestinal mucosa and infects the sites of greatest pigment absorption in the intestine of birds [15].

The optimum pH of gastrointestinal tract is crucial for the action of digestive enzymes. However, coccidiosis infection has been responsible of causing malabsorption of nutrients which is related with the alteration of pH and morphological alteration including flattened villi and elongated [16]. The intestinal content was significantly lower in pH in birds after 5–9 days post infection of *E. acervulina, E. mivati, E. maxima, E. necatrix* and *E. brunetti* than in uninoculated control birds causing the impairment in absorption of nutrients [17]. Consequently, *Eimeria*induced pH reductions likely impact nutrient digestion and absorption in the intestinal lumen. Also, pancreatic and mucosal brush border enzyme activity is affected at the tissue of infection, whereas brush border enzyme activity may be altered in uninfected intestinal regions compensating for losses in nutrient recovery [18]. Decreased activities of digestive enzymes located on the upper half of the villi, such as disaccharidases, indicate a damaged brush border with a decreased digestive absorptive capacity [16].
