Effect of Dietary with Different Energy and Protein Levels on Laying Quails Performance

protein


INTRODUCTION
Quail is one of the potential livestock in Indonesia.They have several advantages, such as fast growth, high egg production, lesser space and feed requirements, and cheaper capital investment (Agboola et al. 2016).For that reason, quail is suited for both industrial and smallscale farming to produce eggs and meat.According to DGLAH (2021), the quail population in 2017 was 14.6 million birds, while in 2021, the population increased to about 15.2 million birds.Furthermore, in terms of productivity, the quail egg production in 2017 was 25.0 thousand tons, while in 2021, was increased to about 25.3 thousand tons.These data prove that quail farming is essential to fulfilling animal product demand in Indonesia.
The performance of quail is a function of several production factors, one of which is feed.In Indonesia, protein sources are still imported, such as soybean meal, corn gluten meal, distillers' grain, solubles, and meat bone meal (Rakhmawati et al. 2022).The primary source of dietary energy for quail comes from corn.Edi (2021) stated that 70% of the energy requirement for poultry comes from corn, and the rest comes from protein and other nutrient sources.Prices of maize and imported feedstuffs tend to fluctuate and have an upward trend so that they will be correlated with the feed price.
Commercial quail feed has a higher nutrient content than the Indonesian National Standard SNI 01-3907-2006 for laying quail feed.The crude protein content of commercial quail is around 19-22%, while the standard in SNI is at least 17%, and the metabolizable energy is 2700 kcal/kg.Protein is one of the essential nutrients in poultry, and the availability of energy supports chicken activities and production goals (Saraswati et al. 2017;Andri et al. 2020).In addition, protein content functions for growth and production (Silodae & Polakitan 2018).Excess and lack of protein will have a negative impact biologically and economically.
One of the determinations of feed ingredients is more focused on the cost per unit spent to get the cost per unit product (meat, eggs) (Samadi 2012), meaning the comparison of production with costs incurred per unit of production.Therefore, efforts to increase feed efficiency can be made, including by making feed formulations with the right nutrient balance as needed.Macro-nutrients that can be used as indicators of nutrient balance in poultry are crude protein and metabolizable energy.However, to date, the optimum nutrient content for the performance of laying quails still needs to be revised.For that reason, the effects of feeding diets with different metabolizable energy and crude protein levels on the performances of laying quails were evaluated in this study.

Birds and diets
A total of 540 laying quails aged eight weeks were involved in this study.The laying quails were acclimatized for one week before experimental treatments.At this period, the initial egg mass of laying quails was recorded at 7.29±0.72g (coefficient of variation was 9.88%).The laying quails were randomly assigned to nine dietary treatments.Each treatment consists of four replicates with 15 laying quails per replicate.Dietary treatments consisted of three dietary ME (metabolizable energy) levels (2700, 2800, and 2900 kcal/kg) and three CP (crude protein) levels (17, 19, and 21%) in a factorial arrangement.The ingredients and nutrient composition of the dietary treatments are shown in Table 1.Diets were offered in mash form, with the amount of 30 g/bird/day.Drinking water was provided ad libitum throughout the experimental period.The feeding trial was conducted for five weeks.

Laying performance
Feed intake (g/bird/day) was calculated by a formula = offered feed -refused feed (Habsari et al. 2018).Egg production (%) was calculated by a formula = (number of egg/number of laying quails) x 100% (Sartika & Iskandar, 2019).A digital balance determines egg weight (g) (Edi et al. 2018).Egg mass (g/bird/day) was calculated by a formula = egg production x egg weight (Dijkslag et al. 2021).Finally, the feed conversion ratio was calculated by a formula = feed intake/egg mass (Leke et al. 2022).

Statistical analyses
Data were presented as means followed by the standard error of means.Data were analyzed using univariate variance analysis, with ME and CP levels regarded as fixed factors.When significant differences were found (P<0.05),Duncan's tests were performed to separate means.Statistical analyses were performed by using IBM SPSS Statistics Version 22.

RESULTS AND DISCUSSION
As can be seen in Table 2, interaction (P < 0.05) between metabolizable energy and crude protein levels was recorded on feed intake.Feed intake was reduced along with the increase in the metabolizable energy when crude protein levels were 17 and 19%.However, the feed intake tended to be improved when high metabolizable energy was combined with high crude protein contents (2900 kcal/kg and 21%, respectively)..No interaction (P>0.05) was recorded on the other variables (egg production, egg weight, egg mass, and feed conversion ratio).As a single factor, different metabolizable energy levels had a significant effect (P<0.05) on the feed conversion ratio of laying quails.Diets containing 2900 kcal/kg metabolizable energy had better results (P<0.05) on feed conversion ratio than those fed diets containing 2,700 kcal/kg metabolizable energy.However, it was observed that different metabolizable energy levels did not significantly affect (P>0.05)egg production, weight, and mass of laying quails In line with the current findings, de Freitas et al. (2005) also found that the increase in energy level caused a linear reduction in feed intake.It was also reported that diets with varying metabolizable energy levels also had a significant effect on the feed intake of quails, in which the diet with high metabolizable energy was associated with reduced feed intake (Jahanian & Edriss 2015).In a study by Ratriyanto et al. (2017), high metabolizable energy also reduced the feed intake of laying quails.The reduction of feed intake due to the higher metabolizable energy content in the feed is probably related to the fact that the feeding activity of birds was aimed at fulfilling the energy requirement.Therefore, when the energy requirement is fulfilled, the birds will stop feeding activity so that the feed intake is adjusted according to the energy content in the feed (Fonseca et al. 2021).The reduction of feed intake due to the increment of dietary energy is also reported in other poultry, such as laying hens (Kang et al. 2018;Granghelli et al. 2019) andducks (Xuang et al. 2018;Awad et al. 2022).
In this study, egg production, weight, and mass did not differ among varying metabolizable energy levels.This finding confirmed the previous study by Agboola ME= metabolizable energy, CP= crude protein, FI= feed intake, EP= egg production, EW= egg weight, EM= egg mass, FCR= feed conversion ratio.a,b different superscripts within a column indicate significant differences (P < 0.05); c,d,e different superscripts within a column indicate significant differences (P<0.05);f, g, h, i, j different superscripts within a column indicate significant differences (P<0.05)et al. ( 2016), who also found that diets with varying metabolizable energy had no significant effect on hen day production and egg weight of laying quails.Similarly, Hijab & Albaddy (2022) also found that diets with varying metabolizable energy did not significantly alter laying quails' hen day production and egg weight.In another study, Ratriyanto et al. (2018) also found that the diet's high and low metabolizable energy contents provide equal egg mass in laying quails.This study found that the high metabolizable energy provides a better feed conversion ratio of laying quails than the low metabolizable energy.In line with this study, Ratriyanto et al. (2018) also observed that feeding high metabolizable energy diets significantly A study by Fonseca et al. (2021) also reported that improved feed efficiency compared to feeding low metabolizable energy diets.feeding diets with high energy content resulted in a better feed conversion ratio than feeding diets with low energy content.Therefore, the better feed conversion ratios reflect the lower feed intake due to the high metabolizable energy content in the diets.
Table 2 shows that the crude protein as a single factor significantly affects (P<0.05)egg production, egg weight, egg mass, and feed conversion ratio of laying quails.The increase in crude protein levels from 17, 19, to 21% gradually improved (P<0.05) egg production, weight, and mass but reduced f eed conversion ratio.Regression analyses between metabolizable energy and crude protein intakes on egg production, egg weight, egg mass, and feed conversion ratio of laying quails were also undertaken.The results showed that metabolizable energy intake linearly improved egg production, weight, mass, and feed conversion ratio (Figure 1).Similarly, crude protein intake linearly improved egg production, weight, mass, and feed conversion ratio (Figure 2).Previously, Bouvarel et al. (2010) also showed that a higher energy intake could improve laying performance.In addition, Gunawardana et al. (2008) also observed that increased crude protein intakes could improve laying performance in another study.This finding indicated that metabolizable energy and crude protein were critically important in supporting the production performance of laying quails.
In this study, a diet containing 2900 kcal/kg metabolizable energy and 21% crude protein provides the optimum performance of laying quails.However, the high energy content in the feed could reduce feed intake (Fonseca et al. 2021), and consequently, the reduction of other nutrient intakes will follow it.Therefore, high crude protein should be followed by high-energy diets to fulfill the protein requirement for optimum performance.In addition, feeding high-energy and protein diets could support estrogen synthesis, promoting egg formation and thus improving the production performance of laying quails (Lotfi et al. 2018).

CONCLUSION
According to the results of the current study, feeding diets containing 2900 kcal/kg metabolizable energy and 21% crude protein are required to provide optimum performance of laying quails.

Table 1 .
Ingredient and nutrient composition of the experimental diets

Table 2 .
Effects of feeding diets with different metabolizable energy and crude protein levels on performances of laying Japanese quails