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LACTOFERRiN ANO IMM U NO GLOBULIN IN CAMELS V:lK

mg/mL), wliicłi is couipaniblc to thc 132.5 mg/mL fuund in thc only milk sainple obtained at thc first inilking in uur survey. This concentration foli sharply but thc level stayed above 4.82 mg/mL at d 7. This trend was similar to those described by El-Hatmi et al. <2006>and El a gamy 11998). Of course, our results were obtained from different animals, in oontrast to those in the refer-ences mentkmed. However, our results are consistent with other data published on camel colostrum (Ungar-Waran et al._f 1987). On average, the IgG ooncentration in camel colostrum seemed to be higher than that in other spedes (El-Hatmi et al., 2006). In the Bactrian camel, Zhang et al. (2005) mentioned that IgG repre-sented 0.90 to 2.52% of the total proteina trom d 1 up to d 7. In our results, the IgG was between 6.6 and 49.1% (mean 19.5 ± 17.1%) of tlie total protein. The results of Zhnng et al. i2005)could bedebatable, possi-bly because of a misreadmg of the SDS-PAGE owing to the segmentation mto H and L chains of IgG.

In the study by Elagainy (2000). the IgG concentra-tion in late-lactation camels milk was higher than that in our results >2.217 vs. 0.718 mg/wL>. In any casc. those values uppearcd higher than thc IgG conccntra* tion obscrved in cow’s milk: 0.520 ± 0.064 mg/mL (Eln-gamy, 2000). In thc Bactrian camel. the IgG concentra-tion was 0.65 to 1.60% of total protein (Zhang et al.. 2005), comparable to our data (0.61 to 2.97%: mean 1.24 r 0.53%).

Lf and IgG Correlation

To our knnwledge, no data showing the correlation between 1/and IgG in camel’* milk is avnilable in the literaturę. The ohserved correlation in our re9ults was significant, but some milk sainple* were rich in both LF and IgG. Tho&e rare milk samples allowed us to build a regression linę, but with a high error type. Most of those samples were spring milk from the Bactrian breed at Atyrau, close to the Caspian Sea. Omission of those outstanding point* led to a lower correlation cocfficient <0.34). which is at the limit of the significant level. It is probably moro eon vc ni en L to consider different types of milk with liigłi concentrations of Lf and IgG comparod with poor milk (Iow conoentnilions of both proteins), as we proposed.

Lf and IgG in Shubat

The fermentation prooess leads to the degradation of proteina in the milk. In Kazakhstau, traditionaliy the milk is not heated before the fermentation process. Tluis, the ol>serv<*J degradation cannot be attributed to heat denaturation Elsewhere, the ring-shaped pre* cipitates observed with shubat samples were very pale, which is characteristic of proteolysis, as has been obecne d in cotnpurison with beat-tren ted samples >Lev-ieux et al.. 2005). In shubat, Lf and IgG are probably mainly hydrolyzed into polypeptide* with similar anti-genic properties as the original protein. This degradation is inereased with the age of the shubat. Moreover, the technolog)’ for shubat fermentation is neither con-trolled nor standard i zed. Thus, the degree of fermentation is not known (i.e., the importance of the protein hydrolyzing,*. With the niethod of Manrini et al.«1965 > for SRID, the antilxxiies, and the standards used in the current study, it was not possible to take in acooimt the content of polypeptides and to differentiate them from the original protein*. The yalues obtained in some samples from our study oould be attributed to •‘young" shubai at tlie beginning of the protein degradation pro-cess. No data on this prooess are available in the literaturę.

CONCLUSIONS

Lactoproteins such as Lf and IgG are known os heallh factors that play an important role for milk consumers. In particular, camel’* milk, which is consumed in many countries (such as Kazakhstan) for its medicmal vir tues, is renowned for being richer in some lactoproteins oompared with cow> milk. In fact. tJie concentrations of 1/and IgG in camel’* milk seem to be only slightly higher than those in other milks. However_f this ąnanti-tative difference does not ezplain the highly renowned quality of camels milk. The quantity of those proteins is probably not the only aspect particular to camels milk. Other proteins such as lysozyme. lactoperoxidase. and growtli factur* could be linked to its health effeets.

Our results showed that the difference between Bac trian and Dromedary camels milk was not elear with our observational design, and that the seasonal effect was morę important than other variatxon factors. The seasonal effect is a comp!ex factor Uiat indudes a cam-el's physiological status and feeding. However. these results are a first step toward oxplaining the observed yariability in cainds milk.

ACKNOWLEDGMENTS

The study was supported by the Frencli Ministry of Forcign Affairs lECONET Programinc) and by thc French Etnbassy at Almaty (Kazaklistan). We thauk also the Kazakh farmer* for their continuing hospi-tality.

REFERENCES

Bart our, E. K., N II. Nat»but>W M PwrirlM, <ti>«l II M AINaklili. ITah-i InhitiiKui of |-<«tlvi^».iłir Imrterłn t*y    milk: Refatfeui

lowlio)*ły*onn**aiul ^iMiflłWtuticin. J Ptoil    mu.

Journal cf Dair>' Scionco Vol 90 No 1, 2007