In vitro and in sacco ruminal protein degradability of common Indian feed ingredients

Protein degradability by in sacco method and protein fractionation by laboratory analysis using CNCP (Cornell Net Carbohydrate and Protein) system was determined to develop a prediction equation for predicting degradability from different protein fractions.

Sixteen different types of feeds namely, maize grain (MZ), maize gluten meal (MGM), maize fibre (MF), maize oil cake (MOC), wheat (WT), wheat bran (WB), barley (BRL), soybean meal (SBM), sunflower meal (SFM), deoiled coconut cake (DCC), cottonseed cake (CSC), groundnut cake (GNC), mustard cake (MC), fish meal (FM), guar chuni (GC) and subabul leaves (LLM) were analysed for (A+B₁), B₂, B₃ and C. The above feeds were also incubated in the rumen of three fistulated, adult crossbred cattle to estimate the effective protein degradability (EPD) of individual feeds. A linear regression equation was drawn for EPD from different protein fractions.

Higher A+B₁ fraction was observed in MC, GNC and BRL, whereas lower values were noted in MGM, MF and MZ. B₂ fraction was highest in MF followed by MZ and LLM and lower values were found in GNC, MC and SBM. B₃fraction was greater in MGM, FM and CSC, whereas the lower values were noted in MC, LLM and MF. Lignin bound nitrogen or C fraction was greater in MGM, GC and LLM and with lower values in BRL, WT, WB, MF and MZ. Higher EPD was found in MC, GNC followed by BRL, MOC and WB, whereas lower values were obtained in MGM, MF, LLM and CSC.

ECPD at different outflow rates were highly and positively correlated (r = 0.84 to 0.88) with (A+B₁) fraction, whereas with B₂, B₃ and C it was negatively associated (r = 0.55 to 0.62, 0.29 to 0.32 and 0.50 to 0.52 for B₂, B₃ and C, respectively).

Therefore, to avoid the maintenance of fistulated animals and to save time for in sacco experiment, laboratory analysis of protein fractions and fitting them in the regression equation may predict the EPD values effectively.

Key words: Indian feeds, prediction equation, protein degradability, protein fractions

Introduction

The rate and extent of protein degradability of different feed ingredients varies considerably with protein source and animal species, which ultimately determines the incorporation of feed ingredients in the diets of ruminants.(Kandylis and Nikokyris 1999, Bach et al 2005) It is suggested that there should be enough soluble readily fermentable protein to support microbial growth and fermentation in the rumen for optimum utilization of roughages, and a source of less fermentable protein, which can pass directly to the abomasum and small intestine for a normal proteolytic digestion and absorption process for optimal performance in high-producing ruminants (Tamminga 1979, Broderic et al 1991, Mathis et al 2000). Therefore, information of protein degradability of various feedstuffs that are available locally is needed for formulation of diets using these feeds.

The degradability can be measured by in vivo methods (Chaturvedi and Walli 1995) and in vitro methods (Walli et al 2000). In vitro methods are quicker for screening of large number of feeds but do not give protein degradability in absolute terms. In sacco method is widely accepted to measure the degradability, which is analysed by a computer model developed by Orskov and McDonald (1979). But result obtained may differ depending on bag pore size, fineness of grinding, sample size, sample size to bag surface ratio, position of the bag in the rumen, microbial population/ contamination of bag residues and incubation time (Micchalet- Doreau and Bah 1993, Nocek 1988, Stern et al 1997). To avoid these problems and maintaining fistulated animals for the in sacco studies, Chalupa and Sniffen (1996) proposed partitioning of protein by subjecting the feeds to digestion in different solvents/ detergents based on Cornell Net Carbohydrate and Protein (CNCP) model. Database for different protein fractions have been estimated from a number of feedstuffs (Sharma and Singh 1997a) and for formaldehyde treated groundnut cake and mustard cake at three different levels (Chatterjee 1998). The present study was conducted to determine in vitro and in vivo degradability of some common Indian feed ingredients, and to develop prediction equations for effective protein degradability on the basis of different protein fractions.

Materials and methods

Sixteen common feedstuffs viz., maize grain (MZ), maize gluten meal (MGM), maize fibre (MF), maize oil cake (MOC), wheat (WT), wheat bran (WB), barley (BRL), soybean meal (SBM), sunflower meal (SFM), deoiled coconut cake (DCC), cottonseed cake (CSC), groundnut cake (GNC), mustard cake (MC), fish meal (FM), guar churi (GC) were procured from local market near by Karnal region of Haryana, India and subabul leaves (LLM) were collected from trees planted around the fodder farm of the Institute. All the samples were ground to pass 2.5 mm sieve size and N content was estimated by Kjeldahl’s method (AOAC 1984). In sacco study was conducted on three fistulated adult male crossbred cattle, kept on a constant diet of concentrate to roughage (35:65) as per NRC (1989) to meet their maintenance requirement. Pre-weighed nylon bags (Nocek 1988) containing 5 g of milled samples were placed inside the rumen of each animals. The samples were taken out at 3, 6, 12, 36, and 48 h interval and thoroughly washed and bags were dried in an oven first at low temperature (60 ºC) and then at higher temperature (90^oC) to determine DM and N loss in rumen. Dry and protein disappearance data were fitted to the model of Orskov and McDonald (1979) to estimate the kinetics of degradability of DM and CP such as a, b and c.

The effective degradability (P) of DM and CP was calculated using the equation shown below, using rumen fractional outflow rates (r) of 0.02 and 0.04 and 0.06 h^-1

Fractionation of protein was done as per Chalupa and Sniffen (1996). Accordingly, different protein fractions were calculated:

(A + B₁): Corresponds to non-protein nitrogen and rapidly degradable true proteins (all globulin and some albumin). This fraction is soluble in phosphate buffer.

B₂ : (PBIN - NDIN) is rest of albumin and all glutelins. This true protein have intermediate degradation rate.

B₃ : (NDIN - ADIN) is prolamins, extension proteins and denatured protein, and is slowly degradable.

C : It is derived fromacid detergent insoluble nitrogen (ADIN). This fraction corresponds to Maillard products and N bound to lignin.

Statistical analysis

One-way analysis of variance (ANOVA) using SPSS (2001) was carried out to compare the data of in sacco degradability values, RDP and UDP content, and different N fractions of feeds. The significance among the individual means was identified using Tukey’s multiple range test. Simple Pearson correlation between effective degradability of CP and different N fractions of feeds estimated using SPSS (2001). Stepwise multiple regression procedure of SPSS (2001) was conducted to predict the effective crude protein degradability (ECPD) from different N fractions with their quadratic terms included for the model development.

Results and discussion

In sacco degradability of DM and CP

Degradation constants (a, b and c), potential and effective degradability for DM at different rumen fractional outflow rates is shown in Table 1.

Table 1. Dry matter degradation kinetics and effective dry matter degradability (EDMD) of different feeds
Ingredients	a	b	c	EDMD at outflow rate, h^-1
Ingredients	a	b	c	0.02	0.04	0.06
Mustard cake	68.38^k	31.62^a	0.033^abc	88.10ⁱ	82.73^g	79.66^g
Groundnut cake	46.41^j	42.36^a	0.091^ef	81.26^hi	75.90^fg	71.98^fg
Barley grain	40.39^ij	44.86^a	0.069^de	72.83^fgh	66.87^def	62.76^ef
Maize oil cake	1.98^a	98.01^f	0.052^cd	72.61^fgh	57.23^cd	47.36^c
Wheat bran	28.99^fg	59.74^bc	0.072^de	75.77^gh	67.47^ef	61.68^e
Wheat	11.02^bcd	83.55^e	0.097^f	80.61^hi	70.45^ef	62.88^ef
Deoiled coconut cake	30.22^gh	69.77^cd	0.021^ab	65.52^def	54.05^c	48.26^cd
Guar chuni	21.31^ef	64.80^bcd	0.067^de	72.75^fgh	63.14^cde	56.56^cde
Sunflower meal	37.76^hi	35.49^a	0.042^bc	61.57^cde	55.71^c	52.18^cd
Soybean meal	25.94^fg	55.82^b	0.112^f	73.15^fgh	66.85^def	62.03^e
Fish meal	8.16^abc	56.66^b	0.055^cd	49.69^b	40.94^b	35.23^b
Maize grain	15.30^cde	64.26^bc	0.027^ab	52.12^bc	41.13^b	35.19^b
Cotton seed cake	38.91^ij	61.08^bc	0.014^a	63.92^def	54.69^c	50.44^cd
Leucaena leaf meal	17.17^de	56.19^b	0.143^g	66.47^efg	61.08^cde	56.76^de
Maize fiber	3.21^ab	96.78^f	0.024^ab	55.78^bcd	39.34^b	30.74^b
Maize gluten meal	5.81^ab	77.80^de	0.012^a	34.85^a	23.69^a	18.73^a
SE	2.16	3.41	0.0067	2.69	2.62	2.50
a, b and c are constants of the exponential equation [P= a+b (1-e^-ct)] where ‘a’ is the rapidly degradable fraction, b the slowly degradable fraction and ‘c’ the rate of degradation of fraction ‘b’, EDMD: effective degradability of DM. ^a-kLetters with different superscripts within a column differ significantly (P < 0.05)

Rapidly degradable fraction (a) was greatest in MC, with intermediate values in GNC, BRL, CSC, WB, DCC, SFM and SBM. Other feeds had low ‘a’ values. Potential degradable fraction (b) was higher in MOC, MF, WT and MGM; intermediate values in DCC, GC, MZ, CSC, WB, FM, LLM and SBM and lower values in BRL, GNC, SFM and MC. Rate of degradation (c) of DM was higher in LLM, SBM, WT and GNC, whereas the lower values were obtained in MGM, CSC, DCC, MF, MZ and MC. EDMD at different rumen fractional outflow rate was lower in MGM followed by FM, MZ and MF, and was higher in MC, GNC and WT.

Table 2. Crude protein degradation kinetics and effective protein degradability (EPD) of different feeds
Ingredients	a	b	c	ECPD at outflow rate, h^-1
Ingredients	a	b	c	0.02	0.04	0.06
Mustard cake	46.40^j	57.72^a	0.060^defg	84.78^fg	76.87^g	71.77^f
Groundnut cake	26.98^gh	70.38^e	0.107ⁱ	86.28^g	78.21^g	72.08^f
Barley grain	22.51^fg	72.26^ef	0.104ⁱ	83.10^efg	74.68^fg	68.32^f
Maize oil cake	13.54^cd	82.86^gh	0.075^gh	78.96^def	67.58^ef	59.57^e
Wheat bran	12.91^cd	78.48^fg	0.090^hi	77.08^de	67.18^e	59.94^e
Wheat	10.00^bc	89.99^ij	0.064^efg	78.54^def	65.35^de	56.42^e
Deoiled coconut cake	22.45^fg	77.54^fg	0.049^def	77.50^de	65.13^de	57.30^e
Guar chuni	21.53^f	67.60^cde	0.068^fgh	73.75^cd	64.07^de	57.42^e
Sunflower meal	38.18ⁱ	61.81^bcd	0.025^abc	72.38^cd	61.86^de	56.29^e
Soybean meal	23.04^fg	60.95^bc	0.058^defg	68.21^c	58.94^d	52.83^e
Fish meal	20.06^ef	57.62^ab	0.045^cde	59.94^b	50.56^c	44.75^d
Maize grain	31.50^h	68.49^de	0.012^a	57.14^b	47.28^bc	42.90^cd
Cotton seed cake	16.73^de	83.26^ghi	0.022^ab	60.33^b	46.27^bc	39.07^bcd
Leucaena leaf meal	6.03^b	78.52^fg	0.038^bcd	57.63^b	44.39^bc	36.56^bc
Maize fiber	7.71^b	92.28^j	0.023^abc	57.01^b	41.36^b	33.26^b
Maize gluten meal	0.13^a	87.23^hij	0.011^a	30.94^a	18.88^a	13.60^a
SE	1.23	1.85	0.0060	1.83	1.96	1.95
a, b and c are constants of the exponential equation [P= a+b (1-e^-ct)] where ‘a’ is the rapidly degradable fraction, b the slowly degradable fraction and ‘c’ the rate of degradation of fraction ‘b’, ECPD: Effective degradability of crude protein. Letters with different superscripts within a column differ significantly (P < 0.05)

The values of ‘a’ for CP were high in MC, SFM, MZ and GNC followed by in SBM, DCC, BRL, GC and FM, and was low in other feeds. Potential degradability (b) of CP was greater in MF, WT, MGM, CSC, MOC, LLM, WB and DCC, whereas low values were obtained in FM, MC, SBM and SFM. Rate of degradation for CP was higher in GNC, BRL, MOC and WB, and was lower in MGM, MZ, CSC, MF and SFM. The ECPD values ranked MGM < MF = LMM = CSC = MZ = FM < SBM ≤ SFM = GC ≤ DCC = WB ≤ WT = MOC ≤ BRL ≤ MC ≤ GNC at fractional outflow rate of 0.02 h^-1. Same trend also followed in other rumen outflow rates. Out of 16 feeds, most of these viz., MOC, SFM, SBM, BRL, WT, WB, DCC, GC, GNC, MC had high (> 55%) ECPD at fractional outflow rate of 0.04 h^-1.

Murphy and Kenelly (1987), Walli et al (1991) and Woods et al (2002) observed similar trend in ECPD value for BRL, whereas Mustafa et al (1998) reported lower ECPD value, which may be due to difference in milling of the grain. Zerbini and Polan (1985) and Sharma and Singh (1997b), Murphy and Kennelly (1987), Walli et al (1991) and Haldar and Rai (2002) reported a different value for MZ. For CSC, Sharma and Singh (1997b) reported a similar value, but Walli et al (1991) reported a lower value and Zerbini and Polan (1985) and Haldar and Rai (2002) reported a higher value of ECPD. Ha and Kennelly (1984), Zerbini and Polan (1985) reported a lower ECPD value for FM, whereas Siddons et al (1985) reported a higher and Woods et al (2002) observed a similar ECPD value for FM. This may be due to type of fish used for preparation of meal and processing of the feed. In case of SBM, Ha and Kennelly (1984) and Walli et al (2000) reported a little difference in EPD value, but Santos et al (1984), Zerbini and Polan (1985) and Woods et al (2002) reported a higher EPD value. In case of SFM, Sharma and Singh (1997b) and Woods et al (2002) observed a higher ECPD value for SFM. For WB, Walli et al (1991) and Sharma and Singh (1997b) reported a similar ECPD value however, Haldar and Rai (2002) observed a different EPD value. LLM, which is also a high protein source, had the similar EPD value as reported by Sampath et al (1989). ECPD of GNC was similar as reported by Haldar and Rai (2002) but for MC they reported a lower value.

UDP content of feeds

UDP values were calculated from ECPD at different rumen outflow rates for each feed and presented in Table 3.

Table 3. Crude protein (CP) and rumen undegradable protein content (RUP, % DM basis) of some common feeds at different rumen fractional outflow rates
Ingredients		CP	UDP at rumen outflow rates
Ingredients		CP	0.02	0.04	0.06
Mustard cake	1	33.18^de	5.12^bc	7.76^cd	9.45^de
Groundnut cake	2	43.19^f	5.92^c	9.40^d	12.06^e
Barley grain	3	10.25^a	1.73^a	2.60^a	3.26^a
Maize oil cake	4	21.00^b	4.42^abc	6.80^cd	8.49^cde
Wheat bran	5	13.56^a	3.12^abc	4.46^abc	5.45^abc
Wheat	6	8.94^a	1.92^ab	3.11^ab	3.91^ab
Deoiled coconut cake	7	25.50^bc	5.74^c	8.89^d	10.89^e
Guar chuni	8	55.12^h	14.46^ef	19.79^gh	23.45^hi
Sunflower meal	9	36.31^e	10.04^d	13.86^e	15.88^f
Soybean meal	10	54.81^h	17.44^fg	22.51^hi	25.85^ij
Fish meal	11	49.06^g	19.66^g	24.27ⁱ	27.12^j
Maize grain	12	12.56^a	5.36^c	6.60^bcd	7.15^bcd
Cotton seed cake	13	29.19^cd	11.58^de	15.69^ef	17.79^fg
Leucaena leaf meal	14	32.87^de	13.92^e	18.28^fg	20.85^gh
Maize fiber	15	10.12^a	4.36^abc	5.95^abcd	6.76^abcd
Maize gluten meal	16	70.31ⁱ	48.56^h	57.04^j	60.75^k
SE		1.305	0.894	0.956	0.990

Although UDP content (%DM) differed depending upon the rumen outflow rates, it was greatest in MGM, followed by moderate quantity in FM, SBM, GC, LLM, SFM and CSC, low quantity in DCC, GNC, MC, MOC and MZ. UDP content was lowest in BRL, WT and WB. Haldar and Rai (2002) reported a similar UDP value for GNC and WB whereas different value for MZ, CSC, MC and MGM. On the basis of UDP values, it may be suggested that MGM, FM, SBM, GC, CSC and LLM are good source of naturally occurring bypass protein.

Fractions of protein in different feeds

Crude protein is the heterogeneous mixture of true protein and NPN. The protein fractions in the feed affect both ruminal degradability and digestion of undegradable protein in the small intestine. A method of partitioning proteins by subjecting feeds in different solvents and detergents have been developed by Chalupa and Sniffen (1996). Results of different protein fractions are shown in Table 4.

Table 4. N solubility and protein fractions in different feeds (% of total N)
Ingredients	PBSN (A+B₁)	PBIN	NDIN	B₂	B₃	ADIN (C)
Mustard cake	76.24ⁱ	23.76^a	13.19^a	10.57^b	9.96^a	3.23^ab
Groundnut cake	74.15ⁱ	25.85^a	20.50^cd	5.35^a	15.33^b	5.17^abcde
Barley grain	51.35^h	48.65^b	36.49^gh	12.16^bc	32.31^fg	4.18^abcd
Maize oil cake	35.61^de	64.39^ef	26.79^ef	37.60ⁱ	20.81^c	5.98^bcdef
Wheat bran	46.51^gh	53.49^bc	23.39^de	30.10^gh	20.32^c	3.07^a
Wheat	37.80^def	62.20^def	31.76^fg	30.44^h	27.59^de	4.17^abcd
Deoiled coconut cake	43.80^fg	56.20^cd	43.27^ij	12.93^bc	38.18^hi	5.09^abcde
Guar chuni	46.41^gh	53.59^bc	32.82^gh	20.77^def	25.27^d	7.55^ef
Sunflower meal	37.71^def	62.29^def	36.95^h	25.34^fg	31.13^ef	5.82^abcde
Soybean meal	41.61^efg	58.39^cde	42.49ⁱ	15.90^cd	35.70^gh	6.79^def
Fish meal	27.82^bc	72.18^gh	47.82^j	24.36^ef	44.32^jk	3.50^abc
Maize grain	23.72^b	76.28^h	18.75^bcd	57.50^j	14.78^b	3.97^abcd
Cotton seed cake	32.10^d	67.90^fg	47.82^j	20.08^de	41.49^ij	6.33^cdef
Leucaena leaf meal	25.41^bc	74.59^gh	17.55^abc	57.04^j	9.97^a	7.58^ef
Maize fiber	20.41^b	79.59^h	14.83^ab	64.76^k	8.91^a	5.92^abcdef
Maize gluten meal	11.65^a	88.35ⁱ	54.95^k	33.40^hi	46.17^k	8.78^f
SE	2.03	2.03	1.40	1.34	1.19	0.77
PBSN, phosphate buffer soluble nitrogen; PBIN, phosphate buffer insoluble nitrogen; NDIN, neutral detergent insoluble nitrogen; B₂, (PBIN - NDIN); C, corresponds to acid detergent insoluble nitrogen (ADIN); B₃,(NDIN - ADIN) SE, standard error

The lower values (percent of CP) for PBSN or A+B₁ fraction was in MGM followed by MF and the greater values were in MC, GNC and BRL. NDIN content was greater in MGM, CSC, DCC, FM and SBM, was and lower in MC, LLM and MF. ADIN was highest in MGM followed by LLM and GC, whereas the lowest ADIN value was obtained in WB followed by MC and FM. (A+B₁) represents PBSN portion, which is highly degradable in rumen and B₂ fraction is 5-15% degradable whereas B₃ is only 0.1-1.5% degradable, and C is the fraction that is neither degraded in rumen nor digested in lower tract, and this represents the ADIN portion of the feed. B₂ fraction was higher in MF, MZ, LLM, and was lower in GNC, MC, BRL, DCC and SBM. B₃ portion was greater in MGM, FM, CSC and DCC, whereas the lower B₂ value was noted in MF, MC and LLM. Results of N solubility and protein fractions in some of the feeds are somewhat different than those obtained by Sharma and Singh (1997a) and Chatterjee (1998) which may be due to variation in feed sources, as composition could vary from region to region or from time to time, depending on soil type, fertilization as well as plant variety and the method of processing.

Prediction equation for EPD based on different protein fractions

Correlation coefficient (r) of ECPD at different fractional rumen outflow rates with (A+B₁), B_2, B₃, and C are presented in Table 5.

Table 5. Pearson correlation between effective crude protein degradability (ECPD) at different outflow rates (0.02 to 0.06) and different protein fractions
	ECPD_0.02	ECPD_0.04	ECPD_0.06	A + B₁	B2	B3	C
ECPD_0.02	1	0.99**	0.98**	0.84**	-0.55**	-0.32*	-0.50**
ECPD_0.04		1	1**	0.87**	-0.60**	-0.29*	-0.51**
ECPD_0.06			1	0.88**	-0.62**	-0.29*	-0.52**
A + B₁				1	-0.72**	-0.30*	-0.41**
B2					1	-0.43**	0.17
B3						1	0.20
C							1
A+B₁, phosphate buffer soluble nitrogen; B₂, [phosphate buffer insoluble nitrogen (PBIN) - neutral detergent insoluble nitrogen (NDIN)]; C, corresponds to acid detergent insoluble nitrogen (ADIN); B₃,(NDIN - ADIN) *Correlation is significant at the 0.01 level. Correlation is significant at the 0.05 level.

ECPD values were highly and positively correlated with (A+B₁) fraction, whereas with B₂ and C it was negatively associated with intermediate correlation. ECPD and B₃ was also negatively correlated with low value of r. The prediction equations to determine in sacco ECPD using different protein fractions is shown in Table 6.

Table 6. Stepwise regressions to predict the effective protein degradability from different protein fractions
Dependent variables	Intercept or independent variables	Parameter estimate	SE	P Value	Model R²	RMSE
ECPD_0.02	Intercept	19.07	3.81	<0.001	0.90	4.68
	(A+B₁)	2.10	0.170	<0.001
	(A+B₁)²	-0.016	0.002	<0.001
	B₃²	-0.004	0.001	0.001
ECPD_0.04	Intercept	10.41	4.28	0.019	0.93	4.28
	(A+B₁)	1.43	0.286	<0.001
	(A+B₁)²	-0.009	0.003	0.004
	B₃	1.18	0.460	0.014
	B₃²	-0.024	0.008	0.006
	C²	-0.104	0.036	0.006
ECPD_0.06	Intercept	5.93	4.16	0.16	0.93	4.16
	(A+B₁)	1.210	0.277	<0.001
	(A+B₁)²	-0.006	0.003	0.032
	B₃	1.348	0.447	0.002
	B₃²	-0.027	0.008	0.002
	C²	-0.115	0.035	0.004
ECPD_0.02-0.06: effective crude protein degradability at outflow rate of 0.02 to 0.06; SE: standard error; RMSE: root means square error. A + B₁: phosphate buffer soluble nitrogen; C: acid detergent insoluble nitrogen (ADIN); B₃,(neutral detergent insoluble nitrogen - ADIN)

Significant predicted variables in stepwise regression included (A+B₁), (A+B₁)² and B₃² at fractional outflow rate of 0.02 h^-1 with R² value of 0.90. However, the predicted equations at fractional outflow rate of 0.04 and 0.06 h^-1 contained (A+B₁), (A+B₁)², B₃, B₃² and C²predictive variables with high degree of prediction. Stepwise regression did not include B₂ protein fractions of feeds. Therefore, it seems that (A+B₁), B₃, and C fraction of feeds are most important in predicting ECPD. When slowly degradable protein fraction (B₃) was used to predict the UDP content of feeds, B₃ predicted the UDP content moderately (Figure 1).

However, when the UDP data of some feeds was not included to develop prediction equation from B₃, equation gave high degree of prediction (R² = 0.86). Some of the characteristics of these feeds when not included predicting UDP from B₃ highly is having high fiber content and/or high B₂ content. B₂ protein fraction of feeds is partially digested and thus may contribute to UDP content of feeds. This might be one reason of low prediction of UDP from B₃ when all the data were included. Sharma and Singh (1997b) reported a high R²value for the prediction equation involving ECPD and all the protein fractions of the feed. Similarly Chatterjee and Walli (2002) reported a high R²value for the prediction equation with respect to formaldehyde treated mustard cake and groundnut cake at four different levels.

Conclusions

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In vitro and in sacco ruminal protein degradability of common Indian feed ingredients

G Mondal, T K Walli and A K Patra*

Dairy Cattle Nutrition Division, National Dairy Research Institute, Karnal, Haryana, 132001, India
goutam_mondal@rediffmail.com
*Department of Animal Nutrition, West Bengal University of Animal and Fishery Sciences, Kolkata 700037, WB, India
akpatra75@rediffmail.com

Abstract

Introduction

Materials and methods

Statistical analysis

Results and discussion

In sacco degradability of DM and CP

UDP content of feeds

Fractions of protein in different feeds

Prediction equation for EPD based on different protein fractions

Conclusions

References

In vitro and in sacco ruminal protein degradability of common Indian feed ingredients

G Mondal, T K Walli and A K Patra*

Dairy Cattle Nutrition Division, National Dairy Research Institute, Karnal, Haryana, 132001, India goutam_mondal@rediffmail.com *Department of Animal Nutrition, West Bengal University of Animal and Fishery Sciences, Kolkata 700037, WB, India akpatra75@rediffmail.com

Abstract

Introduction

Materials and methods

Statistical analysis

Results and discussion

In sacco degradability of DM and CP

UDP content of feeds

Fractions of protein in different feeds

Prediction equation for EPD based on different protein fractions

Conclusions

References

Dairy Cattle Nutrition Division, National Dairy Research Institute, Karnal, Haryana, 132001, India
goutam_mondal@rediffmail.com
*Department of Animal Nutrition, West Bengal University of Animal and Fishery Sciences, Kolkata 700037, WB, India
akpatra75@rediffmail.com