Chinese Journal of Animal Nutrition 2007, 19(5)

Effect of Different Levels of Zinc on Blood Physiological and Biochemical

Parameters in Stud Holstein Bulls

XIN Fu-yu1,2 HOU Ming-hai1 LI Wen-li2 LI Yan-qin1 WANG Ling-ling1

SONG Jie1 ZHONG Ji-feng1

(1.Dairy Cow Research Center of Shandong Academy of Agricultural Science, Jinan 250100, China; 2.College of Animal

Science and Technology, Laiyang Agricultural College, Qingdao 266109, China）

Abstract: Thirty breeding Holstein bulls assigned randomly to five groups was conducted to study the effect of different levels of zinc on blood physiological and biochemical parameters. This experiment involved 5 dietary treatments with single factorial arrangement, consisting of one control group fed basal diet and four levels of zinc which is 50, 80, 110, 200 mg/kg (by the dry matter of the dietary). The results shows that (1) the effect of different levels of zinc on the activity of GPT、GOT was extremely significant (P<0.01),but that on AKP, LDH was not significant (P>0.05); (2) the effect of different levels of zinc on the testosterone contents in serum was extremely significant (P<0.01),but that on zinc contents in serum was not significant(P>0.05). All of the variety of physiological and biochemical parameters analysed in each group indicated that the optimal supplementation of zinc was 110 mg/kg by the dry matter in this experiment. Key words: Zinc; Holstein; Stud Bulls; Physiological and Biochemical Parameters

Since Todd Bertrand had proved zinc was the essential trace element for animals in 1934, mass of study had been performed on zinc, it is discovered that the physiological function of zinc were the most of all trace element. It has been proved that zinc participates the composition of 300 kinds of enzymes and function-proteins of the animal in vivo now, it participates on the metabolism of proteins, amino acids, nucleinic acids, fat, carbohydrate and vitamins as well as the metabolism of other trace elements, but also relates to the activity of insulin, glucagons, prostaglandin, gonad stimulating hormone. It is necessary to the physiological function such as the development of ossature, reproduction, immunization, blood clotting,and the stabilization of biomembrane[1-3].Furthermore, zinc is the composition of many function-proteins such Received date:2007-01-05

variety project of Shan Dong

, male, Postgraduate, major in

s on the requirement of zinc, many scho

1 Materials and methods

nd Choice of experimental bulls

In the experiment,30 healthy pure Holstein

Support project: improved Province, No. 2003-3009 Author:Xin Fu-Yu(1982-)ruminant nutrition, E-mail: xinfuyu_2004yjs@126.comCorresponding author: Hou Ming-Hai(1963-), Professor,Animal Nutrition expert, E-mail:minghaihou@163.com

as metallothionein, neucleoprotein and some receptors.

Studielars domestic and abroad has focus on the

suitable supplement to diets of swine and cow, but similar research on breeding bulls is very weak accordingly[4]. Recent studies have confirmed that animal feed which is lack of zinc could influence the growth, development and performance of breeding bulls acutely. According to practic trophic analysis, the content of zinc in common diets for bulls is far lower than NRC standard. This study was carried out for determining the suitable zinc supplement for local Holstein herd sire through detecting some important biochemical indicators in blood with different levels of zinc supplementation, aiming to provide a necessary theoretical basis for scientific raising of herding bulls.

1.1 Experimental design a

XIN Fu-yu et al.: Effect of Different Levels of Zinc on Blood Physiological

breeding bulls with basically consistent physiological condition (815±73 kg in body weight, 2.5~

dition

that the time

Table 1 The composition and nutrient levels of the basal diet (air-dry basis,%)

Ingredient

3.5 years of age, normal Semen Collection twice a week) were assigned at randomly to 5 groups, named group A,B,C,D and E respectively. Each groups had 6 bulls. Simple factor experiment design was designed. Group A was set as control group and the other four groups as experiment groups. Bulls in control group fed with basic daily diet while bulls in experiment groups were fed the diet with different levels of inorganic zinc supplementation(50, 80, 110, 200 mg/kg, calculated by dry material).Zinc used in the study was in form of analytical pure ZnSO4·7H2O. 1.2 Diet composition and feeding management

The rations were determined according to NRC Nutrient Requirement of Dairy Cow (EⅦ ) [5].Basic diets is composed of mixed

concentrate, Lucerne and Leymus chinensis. Bulls were fed fixed quantity (0.5% of body weight) twice a day. The composition and nutrient of the mixed concentrate were shown in Table 1.

The livestock house for experiment was washed and degermed before. Considering

for generation of sperm is about 64~74 days and the time for sperm migration from seminiferous rubule to epididymis where the sperms stored and ripped completely is about 14~18 days[6], The period was divided into two phases including 3 months of pre-experiment period and 5 months of experiment period. Preparing work such as Serial number, helminthicide and body weight adjuster were done in pre-experiment period. Feeding management in the two period was identical.

Content Nutrient Content

Corn 55 DM 86.3 Soybean meal 24.5

Zn(mg/kg)

4 N 6.97

1

CP 13.69 Wheat bran 16 Ca 1.53 Fish meal 2.0 TP 0.33 NaCl 1.0 27 CaHPO 1.5 EL (MJ/kg)*

Total 00.00

Note：The values of nutritient are measure that NEL is calculated.

.3 Sample collection and treatment mples were

co

ent in feed and

mples of feed and serum were treated by Wet-

ion 1ml serum into 25ml conical flask nitric

acid

g north operative

proc

d except

suct1

During experiment period, blood sallected germ freely from vena caudalis in the

middle ten days of each month. The samples were centrifuged in low temperature (4℃) immediately, Serum was separated and collected in order to detect correlated biochemical indicator. 1.4 Detected index and methods 1.4.1 Determination of Zinc contserum

Sadigestion method. Determination of Zinc in feed

and serum by Atomic Adsorption Spectrometry. Operating procedure for serum digestion was:

accurately, add 5 ml High-grade ,digested in constant temperature electric

stove at 200℃. when the mixture become clarify, add 1 ml high-grade perchloric acid,degested till the digest turned achromasy and fume white smoke . Add 10 ml distilled water, degested till the mixture turned achromasy and fume white smoke again. Metered volume the digest to 10 ml accurately. Zinc content was detected with TAS-990 Atomic Absorption Spectrometer 1.4.2 The determination of testosterone

Special kit was bought from beijininstitute of biological technology. The

edure was according to its directions.

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Testosterone content in serum was detected with SN-695 Intelligent γ-radioimmunoanalyzer. 1.4.3 The determination of enzymes activaty

Kits for determinate GPT、GOT、AKP and LDH heng

Bioe

was oper

Table 2 Effect of different levels of Zinc supplement on serum zinc and testosterone

Treatment e (pg/mL)

activity were bought from Nanjing Jiancngineering Institute，The operative procedure

was according to the directions.。Absorptance was detected with UV-9200 UV-Vis Spectrophotometer.

1.5 Data processing and statistical analysis

Single factor analysis of variance ated by ANOVA process of SPSS 11.5.

Multiple comparison was carried out by LSD method. Result shown bellow were indicated in form of “average ± standard deviation”

Serum Zinc (μg/mL) testosteron

A (Control) 2.32±0.28a 4.88±0.69Aa

B (50 mg/kg)

e 0.006

2.46±0.11a 5.61±0.57Aa

C (80 mg/kg) 2.75±0.25a 6.40±0.94Aa

D (110 mg/kg) 2.99±0.19a 9.12±1.38Bc

E (200 mg/kg) 2.85±0.26a 8.51±1.81b

SEM 0.101 0.518 P-valu 0.017

Note：values marked with same small letters in the same were not significant(P>0.05), with mall letters

Results and analysis

ls of Zinc supplement

rone content in expe

there were no distinct differences(P>0.05). With

Table 3 Effect of different levels of zinc supplement on the activity of GPT、GOT、AKP、LDH

Treatment /L)

column different swere significant(P<0.05), with different capital letters were extremely significant(P<0.01). The same below.

2

2.1 Effect of different leveon serum zinc and testosterone

As shown in Table 2, testosteriment groups was higher than control group

significantly（P<0.01）. Zinc supplementation in diet elevated the Zinc concentrate in serum, but

increasing zinc additive, zinc and testosterone content in serum showed a trend that increased at the beginning and then decreased.It indicates that the optimal zinc supplement for breeding bulls is between 50 mg/kg and 200mg/kg.

GPT (Carmen’s unit/ml) GOT (Carmen’s unit/ml) AKP (King's unit/100ml) LDH(U

A(Control) 14.17±1.14Aa 22.60±2.40Aa 12.10±1.14a 6631.70±705.86a

B(50 mg/kg)

b

e 0.155

16.04±1.93a 23.56±2.60a 11.58±1.48a 7078.77±714.25a

C(80 mg/kg) 17.80±1.67a 23.74±2.24a 13.49±1.87a 7031.90±735.59a

D(110 mg/kg) 21.99±2.12Bb 33.27±3.14B 12.14±1.98a 7133.23±774.44a

E(200 mg/kg) 16.31±1.83a 26.88±2.85a 13.65±1.76a 6973.76±816.79a

SEM 0.632 0.868 0.364 330.786

P-valu 0.161 0.001 0.000

2.2 ect of different levels of zinc supplement

y of GPT

LDH activity has no significant change（P>0.05）. Effon the activity of GPT、GOT、AKP、LDH

Date in table 3 indicates that the activit and GOT in experiment groups was higher

than control group significantly(P<0.01), AKP and

With increasing zinc additive, the activity of serum LDH rised earlier but decreased later. However, the activity of serum AKP has no regularity change among groups.

XIN Fu-yu et al.: Effect of Different Levels of Zinc on Blood Physiological

3 Discussion

3.1 Effect of different levels of Zinc supplement

us of bull directly，low level of seru

gland.It also participates in re

、GOT、AKP、LDH

zinc

which exist in chondrosome exten

n diet g bulls elevated the content of

on serum zinc The content of serum zinc reflect the zinc

nutritional statm zinc could influence the performance of bull

seriously。the content of trace element is relatively stable in various kinds of animal’s blood and changing within physiological range when trace element is enough both in diet and animal body. The results showed that, the content of serum zinc is 70-130 ug/100 ml in normal bull. Although various kinds of nutritive material intrance and Exit continuously in blood, the content of serum zinc could recover the balance quickly in healthy animals. In this trial, the concentration of serum zinc in test group was higher than that in control group with zinc supplement, It indicated that zinc supplement in diet could increase the content of serum zinc and improve the zinc nutritional status of bull.Although no significant change was found in the two groups.(P>0.05),there is a positive correlation between serum zinc and diet zinc in a given range. Relative study demonstrated serum zinc began to descend only when zinc in liver and bone descend to critical value. 50% of normal serum zinc is the mark of zinc deficiency. 3.2 Effect of different levels of Zinc supplement on serum testosterone

Zinc is an inherent component of cortical substance of suprarenal

gulating the function of appendices suprasphenoidalis - sexual gland system. The synthesis of testicosteroid depends on the existence of zinc. Zinc plays an important role on testosterone externalization through affecting the release of gonadotropic hormones. Serum testosterone is the total amount of testosterone in blood circulation, in other words, it’s the sum of free testosterone and combined-testosteron. However, what really play biological action in vivo is the free testosterone which account for only 3% of the total. Most of free testosterone exist in seminal plasma. Because of

there are positive correlation significantly between serum testosterone and free testosterone, serum testosterone were reported in many articals according to concerned research on factors affecting the decrease of semen quality so as to reflect the law of change of seminal plasma testosterone [8-9]. As the result of the test shows: Zinc supplement enhanced the synthesis and externalization of testosterone, improved productitive performance of bulls.With increasing zinc supplement,serum testosterone show a tendency that increased at the beginning and then gradually decreased. 3.3 Effect of different levels of zinc supplement on the activity of GPT In recent years , alkaline phosphatase activities is known as a index for the assessment of nutriture. Wright’s research confirmed there were obviously positive correlation between serum zinc and alkaline phosphatase activities.However,the activities of alkaline phosphatase in neutrophil have nothing to do with that in blood plasma. It is therefore considered that simultaneous determination on alkaline phosphatase activities both in neutrophil and in blood plasma can be a reliable determination index of zinc nutriture

GPT and GOT is an important amino acid transaminase

sively.It plays an important role in protein metabolic process,takes participate in the transform and synthesis of various kinds of essential amino acids,lies in special important position in amino acid metabolism and reciprocal transformation of protein,fat and carbohydrate[11-12]. The result of this test indicates that zinc supplement in bull diet can elevate the activities of GPT and GOT significantly, in other words,it can promote the synthesis of protein,decrease the decompose of protein,increase protein deposition in vivo. All result above is identical with the mechanism of growth promotion of zinc.

4 Conclusion

① Different levels of zinc supplement ifor Holstein breedin

Chinese Journal of Animal Nutrition www.chinajan.com

seru

ment can impr

[1] Miller W J, Clifton C M, Fowlei P R. Influence of high ietary zinc on zinc in milk, performance and

[2]6.

plemented with sulfate and amino-complexed

[4]chny- swine and poultry.1999,26(3):16.

] Meng Q X, Nutrient Requirement of Dairy Cow(NRC,2001). Beijing: China Agricultural University Press, 2002. 151-157.

[7]n-Hai: Shanghai scientific and

[8eral status growth and

[9]e performance of Barki

[10 Holstein calves.

[11] . China feed,

[12]ameters about cow. Livestock and

m testosterone significantly, enhanced GOT and GPT significantly too. However, serum zinc,AKP and LDH have no remarkable chang, but have the tendency to rise;

②All indexes in the four experiment groups indicate that suitable dietary zinc supple

ove the nutriture of breeding bulls,100mg/kg addition obtained good results.

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(Editor JI Peng)