The effects of l-carnitine and oregano as feed additives in alternative forced molting programmes on oxidative stress and egg production and quality at the 2nd laying cycle in commercial white laying hens

This research has been carried out in order to determine the effects of forced molting programs induced by feeding the hens an alfalfa based and low Na-Ca induction feed as an alternative to forced molting program with feed withdrawal and the effect of L-carnitine and Oregano plant in powder form as feed additives on the induction period parameters, production period performance and egg quality.A negative control group (K) which was not forced nor provided with feed additive substances and 3 test groups (M: Limestone, Y:Alfalfa, F:Low Ca and Na diet) which were applied with forced molting and one with withheld feeding were used for the study; the forced groups were supplied with L-carnitine (100 ppm) and Oregano plant (5%) powder as a feed additive in determined individual ratios (MC, YC, FC, MK, YK, FK ) and used in combination (50 ppm; 2,5%) in groups (MCK, YCK, FCK,) with 6 repetitions for each group and executed in 13 groups consisting of 15 animals in each repetition groups. During the enforcement period the molted groups were subjected to restricted daylight. The light was increased periodically after the molting period in such a way that the forced groups were subject to 16 hours of light during yield period. During the study period water was provided to all groups ad libitum. The first 14 days of the study was executed as a trial period followed by 22 days of forcing and a laying period of 98 days. At the start of the study all the animals were vaccinated intramuscularly against Newcastle Disease. During the molting period the animals were weighed 6 times and the live weight values were calculated. The molting feed consumption was measured on the 11th and 22nd day of the trial. Blood samples were taken on the 11th and 22nd day of the molting period for biochemical and serological analysis. At the end of the molting period 6 animals from each were weighed for live weight and euthanized after which the weight of various organs were measured as well as the length of their intestines; the right tibia bones were removed in order to determine Ca and P levels. During production period egg production and deaths were measured daily whereas feed consumption and egg weight were measured during 14 day periods. During the production period 18 eggs from each group, the weights of which had been determined, were analyzed for egg quality.During the study an assessment at the 0-11 day interval of the 22 day molting period was made in two periods and 21,03-26,85g of limestone was measured in groups M, 22,60-30,47g of alfalfa powder in groups Y and 104,08-108,49g of molting feed consumption were measured in group F. The body weight losses in the groups during this period was between 22,68-24,71 % in groups M, between 18,6-22,08 % in groups Y and between 2,37-4,90 % in groups F. The production yield for the groups were between 10,93-12,83 % for groups M, between 8,49-10,50 % for groups Y and between 42,83-49,73 % for groups F. By tehe supplementation of feed additives, consumption, live weight loss and egg yield of groups M and Y had not been affected during the 0-11 day period. While feed additives had no impact on consumption and egg production in groups F, it was observed that the addition of oregano plant individually and together with L-carnitine had a decreasing effect on body weight loss. During this period it was observed that the live weight loss targeted with non-feed method asserted in literature was approximated in groups M and although the live weight loss forming in groups Y was less than that of groups M the egg yield was similar to that of groups M. This situation shows that the live weight loss achieved in groups Y with an 11 day molting period ensures sufficient rest. It can be deduced that 11 day molting was insufficient to provide a proper rest for groups F and that the oregano supplement had prevented live weight loss. During the 11-22 day period of the molting groups M with applied feed withdrawal were provided restricted grain. Y groups continued to consume alfalfa meal while our F groups continued to consume low amount of Na-Ca molting diet. In the M groups a consumption of between 33,99-37,98g of barley, a consumption of between 22,51-29,03g of alfalfa meal in groups Y and a consumption of between 64,15-79,21g of molting feed in groups F was measured. During this period it was observed that the live weight gain attributed to barley consumption in M groups increased while the live weight loss in groups Y and F continued. During this period egg laying in groups M and Y stopped completely whereas the egg yield in groups F was between 32,81-37,68 %. During the 11-22 day period the feed additives provided to groups M and Y had no significant impact on consumption. It was observed that low amount of Na-Ca molting feed with individual oregano plant and together with L-carnitine had a significant impact on increasing feed consumption in groups F. It was concluded that low amount of Na-Ca molting feed with oregano prevented live weight loss. Looking at the live weight losses for 0-22 days it can be seen that the values in groups M are between 14,61-17,14 %, while those for Y groups are between 31,14-33,74 % and those for F groups are between 0,66-10,71%. In the assessment of feed supplements regarding live weight loss in M groups the highest live weight loss incurred in MCK, the least live weight loss incurred in group MK, the highest loss in groups Y incurred in Y, the least loss in YCK while the highest loss in groups F incurred in F and the least loss was experienced in group FCK. Egg yield in groups M and Y were similar while the yield of groups F was low; it was observed that the yield of groups F was significantly lower than that of group K in molting period.In the light of this data it could be said that the live weight loss achieved with qualitative alfalfa meal feed restriction exceeds 30% and exceeds the live weight loss ensured by an 11 day feed withdrawal. Although the impact of qualitative feed restriction by using low Na-Ca feed as molting material was more remarkable in the second half of the enforcement it can be said that a 22 day molting period is not sufficient for this method since egg laying continued. The provision of oregano supplement in this application prevented live weight loss and its use is not recommended.During the molting period the livability of groups M and Y were similar; the feed additives given to M groups appeared to have positive impact.It was determined that the forced molting methods and feed additives used in our study had no adverse impact on the immunity achieved in both samples with the Newcastle disease vaccination.It could be said that the alfalfa meal program has a similar effect as feed withdrawal on oxidative stress and that the doses of feed supplements in both programs do not have a significant impact.It might be concluded that individual L-carnitine supplementation of alfalfa meal groups has a decreasing impact of Ca deposition and numerically groups consuming feed additives with low Na-Ca rations decrease Ca deposition. It was concluded that supplementing L-carnitine to feed withdrawal groups and the addition of both feed additives in F groups increased P deposition.Taking the live percentage of the measured organ weights and lengths into consideration it was concluded that as molting material alfalfa meal had similar effects as feed withdrawal.Post molt period of our study, the production period performance for 98 days was assessed and differences between egg yield averages for groups were observed and it was noted that with the exception of FCK group the yield of all trial groups was significantly higher than the yield of the control group. It was determined that groups M (83,18%), MC (84,24%), MK (83,77%) and YCK (85,19%) had significantly high egg yield while K (64,38%) and FCK (69,90%) g were the lowest yield groups.It was observed that the addition of L-carnitine and oregano plant individually in M groups had a positive impact on egg yield whereas the impact was negative when the supplements were combined. On the other hand, all feed additives given to Y groups had a positive impact on egg production.The egg yield of F, FC, FK groups is significantly lower than that of the other molting groups while it is significantly higher than that of group K. It was concluded that in quantitative terms the FCK group presented the lowest value which revealed similarities with group K.It was concluded that the weight of the eggs obtained from the groups varied between 63,43 g and 67,03 g and a difference among the groups had formed. The significant most heavy eggs came from groups K (66,97 g) and FK (67,03 g) while the lightest eggs were from group YCK (63,43 g). Similarities between groups M and Y were observed regarding average feed consumption and feed conversion ratio for 0-98 days. On average the daily feed consumption ratio per animal in group K was 132,53g whereas group YCK (139,98g) had the significantly highest feed consumption and group F had the lowest feed consumption (124,99g). An assessment of egg quality parameters revealed that the enforcement method and feed additives did not have an impact on eggshell thickness and hough unit during yield period. It was concluded that regarding egg quality the eggs of groups M and Y showed similar effects.Based on these parameters it is concluded that supplementing feed additives into alfalfa meal could be an alternative to the feed withdrawal method and alfalfa meal with a combination of L-carnitine and oregano plant has a positive impact on performance.