Effects of Bypass protein on wool fiber quality
1Dawit Mamo Zegeye
2Tegene Negesse (Professor, PhD)
1Aksum University, College of Agriculture, Department of Animal Science
E-mail: [email protected]
2Hawassa University, College of Agriculture, School of Animal Range Science
E-mail: [email protected]
The paper is aimed to review the effects of bypass protein on wool fiber quality. Different searching engines have been employed to find appropriate information. Fiber diameter is widely acknowledged as the most important wool characteristics when assessing wool quality and value accounting for approximately 75% of the total price of raw wool. Growth of lamb wool fibre is a continuous process influenced by: a genetic basis, nutrition, general physiological status and different environmental factors. Feeding different levels of formaldehyde treated feed ingredients have no effects on wool quality fiber. However, protein containing a high level of sulphur-containing amino acids that is less degradable in the rumen has favour increased wool production. When ruminal degradation of protein is avoided, substantial increase in wool growth rate can be obtained with protein. Finally, research works concerning the effect of feeding by-pass protein are scarce in Ethiopia specifically and in the areas too. This suggests the urgent need to conduct research in this area, which is vital in improving the nutrition and thereby increase the productivity of wool fiber qualities.
Keywords: Bypass; Protein; Sulfur-containing; Wool fiber.
By-pass (rumen undegradable) protein is defined as the proportion of dietary protein that passes from the rumen to the lower digestive tract, without being fermented in the rumen, for digestion and absorption as it would be in non-ruminants (Varga, 2010). Different feeds have varying degrees of naturally protected proteins. Cottonseed cake, maize gluten meal and fish meal are among the naturally occurring rumen by-pass proteins while oilseed cakes like groundnut, mustard and rapeseed are highly degradable in the rumen. These highly-degradable protein supplements need protection against degradation by rumen proteolytic enzymes to increase the flow of protein in to the small intestine (Walli, 2011).
The main interest of protein protection from ruminal degradation is therefore to enhance the supply of essential amino acids to the highly productive animal by preventing rumen degradation of high quality protein and reduction of nitrogen losses as urea in the urine (Kamalak et al., 2005). However, the magnitude of ruminal destruction of dietary proteins varies, and greatest responses can be expected only when rumen soluble proteins are protected. Thus, to obtain responses with supplements of protected protein or amino acids, one must know that amino acids are in short supply for animals performing a particular physiological function (Chalupa, 1975; cited by Kamalak et al., 2005).
Wool growth is a function mainly of the amount of amino acids reaching the intestine (Hynd and Allden, 1985) rather than energy supply (Reis et al., 1992). Furthermore, the amino acid pattern of the protein which reaches the intestine may affect wool growth since sulphur-containing amino acids (SAA) are first limiting in terms of wool protein synthesis (Reis and Tunks, 1978). Therefore, the ruminally degradable proportion of dietary protein becomes a critical factor for wool growth and, on isonitrogenous diets, wool growth responds well to less degradable proteins, particularly when they are high in SAA concentration (White et al., 1999). Consequently, SAA supplementation in the form of methionine, cysteine is effective for enhancing wool growth if degradation in the rumen is avoided (Reis and Tunks, 1978). Therefore, the term paper is aiming to review the effects of bypass protein on wool fiber quality.
Wool Fiber Quality Characteristics
Wool is not a uniform biological product because its physical characteristics vary depending on sheep genetics, environment and management strategies (Warn et al., 2006; Poppi and McLenan, 2010). Wool value is intrinsically linked to its characteristics and the ability to meet commercially pre-determined parameters (Wood, 2003; Jones et al., 2004; Purvis and Franklin, 2005; Bidinost et al., 2008). The quality of wool has determined by the physical and mechanical properties: diameter (fineness), height, length, tortuosity, strength and ductility of the wool fibres (Ružic-Muslic, 2006). In addition, these properties have ascertained by factors of genetic and paragenetic nature. The most important characteristic of wool is definitely diameter (fineness) fibres, which implies an average thickness or diameter of the cross section of fibre expressed in micrometres (µm). Fibre diameter (FD) refers to the average width of a single cross section of wool fibre (Gillespie and Flanders, 2010). It is measured in microns (µm) which equates to one thousandth of a millimetre (Cottle, 1991; Cottle, 2010; Poppi and McLenan, 2010; Rowe, 2010). Fiber diameter (FD) is widely acknowledged as the most important wool characteristics when assessing wool quality and value (Edriss et al., 2007; Kelly et al., 2007; Rowe, 2010) accounting for approximately 75% of the total price of raw wool (Jones et al., 2004; Mortimer et al., 2010).
Growth of lamb wool fibre is a continuous process influenced by: a genetic basis, nutrition, general physiological status and different environmental factors. The potential of sheep for wool production was determined during their embryonic development. During intrauterine development of lambs, begins the formation of the hair, to the extent of which depends on the genetic potential of the animal. The number and size of wool fibres produced by follicles (structural units in the skin of sheep) determine the quantity of wool produced. Primary follicles occur in the skin of the foetus on the ninetieth day after fertilization, while the secondary follicles develop from that moment on until the birth of lambs (Jovanovic et al., 2001). The volume of maturation of follicles and production of wool fibres have closely related to nutrition and intensity of lamb growth. Because the wool fibre is a protein matter whose main ingredient is keratin, the presence and source of protein in the diet affect the yield and quality of fibre (Zeremski et al., 1989). According to the research results obtained by Slen (1969) increase of protein levels from 7 to 10 % in dry matter of isoenergy diet used for feeding sheep, has resulted in an increase in production of unwashed wool by 16 %. At the same time, influenced by the above nutrition treatment, in terms of length and thickness of wool fibre, improvement of 8-12 % was established. In order to investigate the optimal protein content in the diet for maximal growth of high-quality wool fibre, the author carried out a trial on Romney Marsh breed lambs fed diets to suit their basic requirements and rations for fattening with a high proportion of protein in dry matter. It was established that during the period of 6 months of the experiment the lambs fed fattening diets with a high proportion of protein realized by 343 % more of unwashed wool, superior tortuosity of fibre, by 172 % higher fibre, by 206 % stronger and slightly coarser fibre.
Table 1: Relative importance of raw wool characteristics on worsted processing performance
No. Raw wool characteristic Importance
1 Yield ****
2 Fibre diameter ****
3 Length ***
4 Strength/position of break ***
5 Colour ***
6 Coloured ?bres ***
7 Fibre diameter variability **
8 Length variability **
9 Degree of cottedness **
10 Crimp/resistance to compression **
11 Staple tip *
12 Age/breed/category *
13 Style/character/handle *
Notes: ****Most important, *** Major, **Secondary, *Minor.
Source: Anton and Lawrance (2010)
Dietary effect of bypass protein on Sheep Wool fiber quality
Proteins that avoid bacterial hydrolysis in the rumen (undegradable protein), increase the wool production through increase in supply of the organism with amino acids, especially cystine, which is a limiting factor for the production of wool (Dragana Ružic-Muslic et al., 2016). According to Dragana Ružic-Muslic et al., (2016), the infusion of cystine into abomasums or blood cans double the growth of wool, while the infusion of methionine increases the wool growth by providing sulphur for the synthesis of cystine. Another method to protect proteins from degradation in the rumen is treatment with formaldehyde. Zeremski et al. (1989) showed that lambs fed diets supplemented with casein (previously treated with formaldehyde) realized by 70% more wool than those who received untreated casein. Chalupa (1975) studied the impact of application of formaldehyde treated feeds on growth of wool. Comparing the effects of soybean meal (untreated and treated) as the protein source, the author found that the increase of wool in the use treated soybean meal of 117 % compared to untreated (100 %). The use of untreated meat meal as a source of undegradable protein in the sheep diet had a greater effect on the growth of wool (100 %) compared to treated meal (96%). A similar relationship has noted in the use of flax meal (100:92 %). Kiljpa and Kravcov (1989) studied the effect of different protein supplements on the productivity of four (4) groups of sheep. As a source of protein, the Group I used sunflower meal, Group II used peas, Group III soybean meal and Group IV cottonseed meal. Respectively, wool yield in animals at the age of two years was 4.75, 4.78, 5.20, 4.73 kg. Effect of different concentrations of dehydrated alfalfa (0, 5, 10, 15 and 20 %) as source of undegradable protein in the diets for feeding lambs from 17.0 to 36.0 kg on wool production, Urbaniak (1994) found that the greatest accumulation of proteins in wool fibres (4.11 g day-1) was achieved by lambs fed concentrate mixture that contained 10 % of dehydrated alfalfa.
Table 2: The effects of Bypass protein on wool yield, staple and fiber growth in sheep, expressed as the difference with the control treatment.
Bypass proteins BWG (g/day) CWP (g/d) Wool quality Source
FG (µm) SL (cm)
Rapeseed oil meal (HCHO) treated 57** 4.0* 20.5 3.5 G. Habib et al., 2001
Casein HCHO treated 43 8.5 1.9 2.9 J. Kowalczyk et al., 1993
Sunflower oilcake meal 19 1.21* 0.28 0.45 J.A. Baldwin et.al, 1993, J.coetzee et.al, 1995,
RPMet Premix NA 1.27 0.45 0.28 J.A. Baldwin et.al, 1993, J.coetzee et.al, 1995,
Guar meal treated with HCHO NA 213 NA 3.5 O.P, Mathur, 1990
Guar meal treated HCHOand urea NA 218 NA 3.5 O.P, Mathur, 1990
HCHO-treated silage NA 4.46 0.93 3.22 T. N. Barry et al., 1973
+ methionine NA 7.03 0.93 5.22 T. N. Barry et al., 1973
Note: *Significant difference p