Effect of Dietary Electrolyte Balance on Water Intake, Litter Moisture and Production of Broiler chicks at Pre-Starter and Starter Phases

Underestimating the negative impacts of ammonia produced in litters of poultry birds raised under high temperature-humidity index is dangerous, as broiler chickens (BC) are sensitive to high ammonia concentrations which can result in blindness and overall decrease in productive performance. Hence, it is ideal to maintain litter moisture by optimizing the utilization of water by broiler chicks. The balance of acid-base in broilers could be enhanced by supplementing diets or water of BC under heat stress with electrolytes. However, electrolytes increase water intake and might affect litter quality. Therefore, effect of varying dietary electrolyte balance (DEB) on water intake (WI), litter moisture (LM) and productive performance of BC were investigated at pre-starter and starter phases using a total of three hundred, 1-day-old Arbor Acre chicks that were randomly allotted to six dietary treatments [210 (T 1 ), 240 (T 2 ), 270 (T 3 ), 300 (T 4 ), 330 (T 5 ) and 360 (T 6 )] mEq/Kg DEB, in a completely randomised design. Birds were reared at pre-starter phase (PSP) of 0 - 14 days and starter phase (SP) of 14 - 21 days, under the temperature-humidity index of 24.97 - 35.19. Water intake and litter moisture were monitored. Data were analysed using descriptive statistics and ANOVA at α 0.05 . Water intake was enhanced at PSP and SP in birds on 360 mEq/kg, but with increased litter moisture. However, a dietary electrolyte balance of 270 mEq/kg improved performances of broiler chicks at pre-starter and starter phases.


Introduction
Water is crucial in poultry nutrition, as it functions in metabolism, regulation of body temperature, transport of nutrients and excretion of waste materials [1]. [2] reported that it is an acceptable practice to daily monitor birds' water consumption, which gives an early indication of a health problem when water consumption is compared to the standard consumption expected. [3] reported that water consumption in birds can be affected by factors such as environmental conditions; feed and water quality, among others like external air humidity, type and management of a drinker system, age and weight of birds [4]. [5] reported that inadequate management practices in a poultry house leading to increased ammonia concentration in air often result in health problems including contact dermatitis, enteritis and respiratory diseases. [6] noted that drier poultry litter reduces the emission of ammonia into the environment, and this would help avoid environmental and animal welfare problems, with increasing economic profits as one of the end results. Feed ingredients may also affect the rate of water consumption and excretion [7]. However, [2] concluded that daily water consumption is a reliable indicator of broiler performance. Respiratory alkalosis is a product of heat stress, a condition of excess blood bicarbonate reacting with other ions such as sodium ion (Na + ), calcium ion (Ca 2+ ), magnesium ion (Mg 2+ ), and potassium ion (K + ) before being eliminated [8]. Hence, maintenance of bird's acid-base balance is crucial for efficient performance under high temperature as suggested by [9]. Additional potassium and sodium are favorable for birds reared in heat stress environment, but also increases water intake. Therefore, this study aimed at assessing the effect of different dietary electrolyte balance and water intake on the feeding potential and excreta quality of broiler chicks reared under heat stress at pre-starter and starter phases.

Materials and Methods
The protocol for the experiment was reviewed and approved by the Institutional [y] = mineral sources; [c] = other macro ions (Ca, Mg, P, S etc) held constant.
Aggregate DEB = Inherent DEB in rations + DEB in Electrolyte sources.
A total of 38 pens were used in this study in order to measure water intake in heat-stressed broiler chickens as described by the authors. This methodology was premised on the assumptions that the study of water kinetics is important in agricultural research and helps to solve critical issues affecting efficient broiler chicken productivity. To adequately measure actual water intake in birds, 8 pens were randomly isolated. Plastic drinkers of the same size, shape and thickness were put in 38 pens. Equal volume and height of water in the drinkers were maintained daily in the 38 pens. This method is premised on the theories propounded by Pascal's principle of pressure and principle of thermal expansivity of liquids [11]. ( ) 1 2 Actual water intake DER V V = − × where V 1 = Initial volume of water supplied to birds; V 2 = volume left over.
Maximum and minimum average ambient temperature and relative humidity of the pen were monitored on a daily basis using a digital hydro thermometer.
Assay was conducted in each diet for sodium and potassium (Flame spectrophotometer), and chloride (titration) [12] as shown in Table 2. Feed intake was calculated from the difference between supplied feed and feed left in each pen.
Feed weighing was performed on the same dates the birds were weighed. Feed conversion was calculated as the ratio between weight of total feed intake and weight gain within the period in each pen and was adjusted for mortality.
Litter moisture content was evaluated weekly. For each replicate pen, four samples of around 500 g of litter were collected at random locations following equal distances with later homogenization to make a single sample per pen.
Analysis for litter dry matter was performed by oven drying using the forced ventilation method at 55 ± 5 C for 72 h and evaluation by weight difference. Data obtained were subjected to descriptive statistics and analysis of variance using SAS package [13]. Means for treatments in the analysis of variance were compared using Duncan Multiple Range Test and based on probability level of 0.05.

Results and Discussion
At prestarter phase, significant (p < 0.05) differences in dry matter intake of This result has shown that birds 'appetite was not enhanced by dietary electrolyte balance at starter phase. These findings disagree with the report of [14] who stated that regardless of ambient temperatures, increasing DEB stimulated feed intake, which could be the result of increasing Na + levels in diets (0.15% to 0.45%). [15] reported that the weight of birds, when assessed at 42 d, decreased when DEB was lower than 180 mEq/kg and higher than 300 mEq/kg while an optimal electrolyte balance was found for feeds at 250 to 300 mEq/kg. [16]  This result has shown that the intake of water was dependent on dietary cation and anion balance inside the birds. Also, the excretion of excess metabolic acids plus water was not dependent on volume of water taken in by the birds. According to [23], dissipation of more than 80% of the heat produced through evaporative cooling has showcased the importance of increased water consumption in heat-stressed broilers. Water consumption depends on the age of the bird, ambient and water temperatures, physiological state, water pH, levels of macro-nutrients in feed, amount and types of salt added in feed and water. The increase in water consumption benefits the birds by acting as heat receptor and also increases the amount of heat dissipated per breath [22].
The litter moisture content of birds fed varying DEB treatments at pre-starter and starter phases is presented in

Implication
A dietary electrolyte balance of 270 mEq/kg improved performances of broiler chicks at pre-starter and starter phases. Water intake was enhanced at pre-starter and starter phases in birds on 360 mEq/kg but with higher litter moisture.  Means for treatments within a column with no common superscript showed significant (p < 0.05) differences using DMRT, DMI-dry matter intake, BW-body weight, BWG-body weight gain, FCR-feed conversion ratio, DEB-dietary electrolyte balance, p value-probability, SEM-standard error of mean.