Effect of Dietary Supplementation of Chromium Picolinate on Productive Performance, Egg Quality and Carcass Traits in Laying Turkeys

INTRODUCTION

Chromium is an essential trace element in animal nutrition which is required for normal metabolism of carbohydrates, proteins and lipids in humans and laboratory animals (Balk et al., 2007). Research activities of different researchers exploring the effect of chromium on the reproductive ability of livestock have been successfully performed (Lindemann et al., 1995; Amoikon et al., 1995), but research on the use of chromium in poultry is very limited. Dietary chromium supplementation has been shown to positively affect the growth rate and feed efficiency of growing poultry (NRC, 1997; Lien et al., 1999). Being the active component of the glucose tolerance factor, chromium stimulates and regulates the action of insulin (Anderson, 1994); thus it is involved in anabolic and catabolic processes (Colgan, 1993). Seaborn et al. (1994) reported that increasing the effectiveness of insulin, chromium indirectly empowers the ascorbic acid transportation. On the other hand, chromium is thought to be essential for activating certain enzymes and for stabilization of proteins and nucleic acids (Linder, 1991) and it has been recognized that insulin metabolism influences lipid peroxidation (Gallaher et al., 1993). Chromium (insulin cofactor) is, therefore, postulated to function as an antioxidant (Preuss et al., 1997). Chromium deficiency causes disorders of carbohydrate and protein metabolism, reduction in insulin sensitivity in the peripheral tissues as well as a decrease in growth rate (Lindeman, 1996). The positive effects associated with the use of chromium as a nutritional supplement include the reduction of animal sensitivity to negative environmental impacts, enhanced growth, increased proportion of muscle compared with fat, improved production function, support of the immune function etc. Some research has reported that supplementation of dietary chromium, improve the egg production in quail (Sahin et al., 2001), growth performance (Lee et al., 2003) and carcass traits of broilers (Sahin et al., 2002) whereas, others, have reported no positive effect on these same traits (Debski et al., 2004).

A number of studies have investigated the effects of supplementing diets with CrP on growth and reproductive performance and carcass traits of livestock but studies on poultry are very limited. So, the main objectives of this study were to determine the effects of dietary CrP on productive performance, egg quality and carcass traits in laying turkey.

MATERIALS AND METHODS

Experimental population

The present study was carried out at Avian Nutrition and Feed Technology Division, Central Avian Research Institute, Izatnagar, India. Seventy- two (72) female turkeys at 16 weeks of age were housed and distributed randomly into twelve groups each of 6 hens (4 treatments×3 replicates). The experiment had a randomized block design (Snedecor and Cochran, 1985). All the birds were kept in individual cages in a stair-step two-tier system throughout the experimental period. Birds were allowed to eat and drink ad libitum. The trial was terminated at 40 weeks of age. The experiment followed the guidelines of Institutional Animal Ethics Committee of ICAR-Central Avian Research Institute, Izatnagar, India

Experimental diets

Four experimental diets T₁, T₂ , T₃ and T₄ were formulated to contain an additional 0, 250, 500 and 750 µg CrP/kg diet, respectively. The basal diet (T₁) and other CrP treated groups contained same calculated energy (11.97 MJ/kg of diet) and protein (195.90 g/kg CP). Chromium picolinate (CrPic, Chromax®, Prince Agri Products) was used as a chromium source.

Production performance

The body mass of each hen were taken at the end of the experiment with the help of weighing balance. Age at sexual maturity or the age at first lay was measured when the hen started laying eggs. Egg production from each treatment was recorded for a period of 4 weeks (from 37th to 40th weeks). Proper labeling on each egg was done in each and every day.

Egg quality traits

One hundred twenty eggs (10 eggs × 4 treatments×3 replicates= 120 eggs) were collected for this experiment. The egg quality traits like shape index, shell thickness, albumin index and yolk index were estimated according to Singh and Panda (1987). Haugh unit score was calculated by the method described by Kondaiah et al. (1983).

Egg number: Daily egg production was recorded on an individual hen basis and egg number and % egg production was calculated. Certain physical egg quality parameters were measured randomly from ten eggs within each replicate during the last four weeks of the experimental period.

Effect of Dietary Supplementation of Chromium Picolinate on Productive Performance, Egg Quality and Carcass Traits in Laying Turkeys - Image 1

Egg mass: Before starting egg quality traits measurement, each egg was weighed by an analytical balance up to two decimals of a gram.

Shape index: The maximum egg length and width were measured with a Vernier caliper with a resolution of 0.01 cm. The shape index (%) was calculated using the following formula: Shape index= (Maximum width/ Maximum length) x 100

Albumen index: The egg shell was broken at the middle portion with the blunt end of a knife. The egg contents were poured on a perfectly level glass table. Maximum length and maximum width of thick albumen were measured with a Vernier caliper. The height of thick albumen was taken at two spots between the yolk and the outer border of the thick albumen avoiding the chalaza. Albumen heights were measured with a spherometer with a resolution of 0.005 mm, after adjusting for any positive or negative zero error. Albumen index (%) was calculated as per method of Heiman and Carver (1936).

Albumen index= (Albumen height/Albumen width) x 100

Haugh unit: Haugh unit was determined as in Haugh (1937). The original Haugh formula is: H.U.= 100 log - [H- (g(30W^0.37-100)+1.9] / 100

Where, H.U.= Haugh unit; H= Albumen height in mm; g= Specific gravity; W= Mass of egg in g

For ease of calculation this was simplified to

HU= 100 log (H +7.57-1.7W^0.37)

Yolk index: The yolk index was calculated as in Funk (1948). The yolk height and yolk diameter were measured after separating the yolk from albumen.

Yolk index= (Yolk height / Yolk diameter) x 100

Shell thickness: The thickness of three pieces of the shell were measured, two from both ends and one from the middle portion of the egg. The shell pieces were carefully freed from the shell membrane and then thicknesses was measured with a screw gauge accurate up to 0.01 mm after correcting for any positive or negative zero error.

Carcass traits

At the end of the experiment (40th weeks), two birds from each replicate of the treatment (6 birds per dietary treatment) were selected randomly and slaughtered to determine the percentage of the different parts of the carcasses. The carcasses and their parts were weighed without viscera and with skins.

Statistical analysis

Data were analysed using statistical software SPSS 17 version and followed standard procedures for ANOVA (1995) and Duncan’s multiple range test (1955) by comparing means for significant differences.

RESULTS AND DISCUSSION

No any concentration of CrP supplementation had a significant (P>0.05), effect on age at sexual maturity for laying turkey, whereas, egg production and egg mass differed significantly (P<0.05) in T₄ group compared to control and the two CrP treated groups. Egg quality traits in terms of albumin index, yolk index and shape index did not differ significantly (P>0.05) among the different CrP treated and control group. The Haugh unit score and shell thickness were significantly higher (P<0.05) in T₄ treated group than the control (T₁ ) and other two treatment groups (T₂ and T₃ ). Effect of CrP supplementation on egg quality traits is shown in Table 2. The data obtained in the present study are in agreement partially with the results of Sahin et al. (2001) who reported that eggshell thickness, albumen index and yolk index are affected by supplementing chromium picolinate in laying Japanese quails.

The results of the present study are in agreement with Eseceli et al. (2010) and Yildýz et al. (2004), who reported that chromium supplementation did not affect age at sexual maturity in laying turkeys and Japanese quail. The results of the present study indicate that supplementation CrP significantly increased egg production and egg mass in laying turkey (Table 2). The interaction between CrP and age was significant for egg production. Irrespective, of CrP supplementation, means of egg mass was significantly (P<0.05) increased in T₄ group as compared to other three groups. Regardless of laying age, supplementating the diet with 750 µg/kg CrP significantly (P<0.05) increased egg mass, compared with other experimented concentrations and control. The results of increasing egg production and egg mass with CrP supplementation are consistent with earlier reports. Kim et al. (1996) reported that feeding 800 ppb CrP to laying hen diets resulted in higher egg production and egg mass compared with control group. Piva et al. (2003) and Sahin et al. (2001) also reported that supplementation of CrP (400 ppb) increased egg production and improved egg mass in laying hens kept under low temperature.

The possible mechanisms by which chromium could work to maintain egg quality traits for the synthesis of ovomucin which is responsible for gel structure of albumen, and facilitate transfer of cations into the albumen of eggs during the plumping process in the uterus as a structural component of egg albumen or in the cross linking of proteins (Hossain, 1998). On the contrary of the present study results, Eseceli et al. (2010) and Uyanik et al. (2002) indicated that chromium picolinate supplementation increased albumen and yolk index in Lohman white laying hens. These findings strongly suggest that CrP is involved in maintenance of the normal physical state of egg albumen. Anderson (1994), reported that increasing egg shell thickness may be because CrP stimulates and regulates the action of insulin thus increasing the effectiveness of insulin, whereas, Seaborn et al. (1994) reported that CrP indirectly influences the ascorbic acid transportation which has an important role in egg shell formation. Carcass traits in terms of live body mass, percentage of defeather loss, carcass, wing breast, back, drumstick, thigh and neck did not differ significantly (P>0.05), whereas, percentage of bleeding loss, wings and giblets were significantly higher (P<0.05) in T₄ treated group comparison to other CrP treated and control groups.

Effect of Dietary Supplementation of Chromium Picolinate on Productive Performance, Egg Quality and Carcass Traits in Laying Turkeys - Image 2

Effect of Dietary Supplementation of Chromium Picolinate on Productive Performance, Egg Quality and Carcass Traits in Laying Turkeys - Image 3

The effect of chromium on carcass traits in broilers has been variable (Anderson, 1994), and the results of the present study are in agreement with this variability. The present experiment showed that CrP supplementation improved some aspects of carcass traits but overall not so positive effects on carcass traits. Jackson et al. (2008) and Debski et al. (2004) reported that chromium has no any positive effects on carcass traits in broiler. The results of the present study are in partial agreement with the above finding because percentage of blood loss, wings and giblets has significant improvement in T4 group (750 µg CrP/kg diet) compared with other two CrP treated and control groups. The massive changes of the size of giblets is not a good sign but in the present study, the size of the giblets were not so massive but there was significant differences in T4 group compared to control and other two CrP treated groups.

CONCLUSIONS

The results of the present study allow concluding that higher level of chromium picolinate (750 µg CrP/kg diet) had a significant effects on performance in terms of egg production, egg mass but no effects on body mass and age at sexual maturity whereas there was no significant effects on egg quality traits except Haugh unit score and egg shell thickness. On the other hand, there was no any significant effect on carcass traits except percentage of blood loss, wings and giblets in laying turkey.

This article was originally published in Animal Nutrition and Feed Technology (2015) 15: 59-66 doi: 10.5958/0974-181X.2015.00007.4.

Effect of Dietary Supplementation of Chromium Picolinate on Productive Performance, Egg Quality and Carcass Traits in Laying Turkeys

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