Effect of Heat Processing of Rubber Seed Kernel on In Vitro Rumen Biohydrogenation of Fatty Acids and Fermentation

Round 1

Reviewer 1 Report

The manuscript by Gunun et al characterizes the effects of heat processing of rubber seed kernel on in vitro rumen biohydrogenation of fatty acids and fermentation. The authors conclude that RHO reduced rumen biohydrogenation of unsaturated fatty acids (UFA). In my opinion, the manuscript is suitable for publication in Fermentation, after the authors have addressed the following comments

Minor comments:

1. L53-L54, ‘in an in situ and in vitro study [9–10]’, please place the reference in their position, e.g., in an in situ (9?) and in vitro (10?) study.

2. L61-L63，‘In our previous studies, we found that ……in dairy heifers [12].’ . Studies or study, please add two or more references.

3. L67, rumen propionate?

4. L107, L108, CP, GE have been defined in L59.

5. L152, add the version of SAS.

6. L257, delete ‘use in’

 

7. L255, while increased…

Author Response

Review 1

The manuscript by Gunun et al characterizes the effects of heat processing of rubber seed kernel on in vitro rumen biohydrogenation of fatty acids and fermentation. The authors conclude that RHO reduced rumen biohydrogenation of unsaturated fatty acids (UFA). In my opinion, the manuscript is suitable for publication in Fermentation, after the authors have addressed the following comments

-Thanks for your recommendation.

Minor comments:

1. L53-L54, ‘in an in situ and in vitro study [9–10]’, please place the reference in their position, e.g., in an in situ (9?) and in vitro (10?) study.

-L53-54: Already changed to “….in an in situ [9] and in vitro study [10]….”, please see in text.

2. L61-L63，‘In our previous studies, we found that ……in dairy heifers [12].’ . Studies or study, please add two or more references.

-L61-65: Already changed to “In our previous study, we found that feeding RSK of 10–25% RSK had no effect on feed intake, digestibility of nutrients, rumen fermentation, microbial population, microbial protein synthesis, or milk production in dairy cattle [12,13]. Chanjula et al. [15] observed that the RSK level of 20% in concentrate could be used to sustain feed utilization, rumen fermentation, or nitrogen balance in goats.”, please see in text.

3. L67, rumen propionate?

-L66: Already changed, please see in text.

4. L107, L108, CP, GE have been defined in L59.

-L110-111: Already changed to “CP, GE”, please see in text.

5. L152, add the version of SAS.

-L158: Changed to “….SAS program (version 6.12)…..”, please see in text.

6. L257, delete ‘use in’

-Already deleted, please see in text.

7. L255, while increased…

-L263-264: Already changed to “…..propionate while increased butyrate proportions….”, please see in text.

 

Author Response File: Author Response.pdf

Reviewer 2 Report

General consideration: The general purpose of the article is defined. The aim of this study was to evaluate the effect of different heat treatments of rubber seeds on in vitro rumen biohydrogenation of fatty acids and fermentation.More information is missing in the materials and methods section, and while the variations in the bacterial and protozoan population of the rumen are commenting on the results, nothing about the determination methods is reported.

2. Materials and Methods 2.2. Rubber seed samples

Weather conditions and characteristics of the cultivated land could be added.

2.3. Processing methods

Information is missing on how the samples were divided according to the various treatments and how many samples per treatment.

The information relating to the granulometry chosen for the grinding of the samples is missing.

 

2.4. Experimental design and dietary treatments

Line 108: The reference number of the AOAC method used is missing.

Line 109: The bibliographic reference is missing.

 

Table 1. Ingredients of the diet used in the experiment.

Check the percentages, which turn out to be around 95%, probable rounding error.

Incorporate with additional information on the chemical/nutritional characteristics of the samples used: in particular ash content.

 

2.6. In Vitro Gas Production and Fermentation Characteristics

Specify the choice of interpolating the data obtained from the measurement of gas production, according to Ørskov and McDonald and not according to what is indicated by Groot et al. (1996) specifically for gas production.

 

3.3. In vitro rumen fermentation and microbial population

Data relating to the rumen population are reported, but in no part of the text, and in particular in the materials and methods, are the methods of evaluation and counting of these populations mentioned

 

4. Discussion

The paragraph seems more concentrated on reporting what is in the bibliography than commenting on the data obtained, only in some points.

Please revise the paragraph accordingly.

For example, nothing is reported on the fact that the immediately soluble fraction (a) is always negative. Demonstrating the fact that it would have been better to use another interpolation method, as the one used was born more for the study of rumen degradation kinetics of proteins than for the fermentescibilty of carbohydrates

Author Response

Review 2

 

General consideration: The general purpose of the article is defined. The aim of this study was to evaluate the effect of different heat treatments of rubber seeds on in vitro rumen biohydrogenation of fatty acids and fermentation.More information is missing in the materials and methods section, and while the variations in the bacterial and protozoan population of the rumen are commenting on the results, nothing about the determination methods is reported.

-Thanks for your recommendation.

 

2. Materials and Methods 

2.2. Rubber seed samples

Weather conditions and characteristics of the cultivated land could be added.

-L86-90: Already added to “Weather conditions in Sakon Nakhon, Thailand, during August and September in the rainy season were an average temperature of 27.7 ^oC, a relative humidity of 82.1%, rainfall of 273 mm/day, and sunshine of 5.1 h. The main crops planted include paddy rice, rubber, cassava, sugarcane, and mao (Antidesma thwaitesianum Muell. Arg.) in the surrounding lowlands of Sakon Nakhon, Thailand.”, please see in text.

 

2.3. Processing methods

Information is missing on how the samples were divided according to the various treatments and how many samples per treatment.

-L131-132: We are explained “For each treatment, four replications were made, and there were 20 sample bottles plus 4 blanks, for a total of 24 bottles.”, please see in text.

 

The information relating to the granulometry chosen for the grinding of the samples is missing.

-L99-100: Already changed to “The raw, roasted, microwave irradiation, and hot air oven samples were ground to pass a 1 mm screen”, please see in text.

 

2.4. Experimental design and dietary treatments

Line 108: The reference number of the AOAC method used is missing.

-L109-110: Already changed to “dry matter (DM) (method 930.15), ash (method 942.05), ether extract (EE) (method 920.39) and CP (method 955.04)”, please see in text.

 

Line 109: The bibliographic reference is missing.

-L113: Already changed to “HCN by the method of O'Brien et al. [25].”, please see in text.

 

Table 1. Ingredients of the diet used in the experiment.

Check the percentages, which turn out to be around 95%, probable rounding error.

Incorporate with additional information on the chemical/nutritional characteristics of the samples used: in particular ash content.

-Sorry, the rice bran is missing. We are used rice bran at 5% of DM in TMR and also incorporate with chemical composition in table 1, please see in the table.

 

Item	Heat methods
	CON	RAWR	ROR	MIR	RHO
Diet ingredients, % of DM
Rice straw	40.0	40.0	40.0	40.0	40.0
Cassava chip	24.1	24.1	24.1	24.1	24.1
Oil palm meal	15.0	4.6	4.6	4.6	4.6
Soybean meal	10.0	0.0	0.0	0.0	0.0
Rubber seed kernel	0.0	20.0	20.0	20.0	20.0
Rice bran	5.0	5.0	5.0	5.0	5.0
Urea	2.4	2.8	2.8	2.8	2.8
Molasses	2.0	2.0	2.0	2.0	2.0
Salt	0.5	0.5	0.5	0.5	0.5
Sulfur	0.5	0.5	0.5	0.5	0.5
Mineral premix	0.5	0.5	0.5	0.5	0.5
Chemical composition
Dry matter, %	73.8	71.9	74.8	74.2	79.4
Organic matter, %DM	91.9	92.8	92.8	90.9	92.8
Crude protein, %DM	14.4	14.2	14.5	14.5	14.5
Ether extract, %DM	5.9	10.6	10.7	10.5	10.4
Neutral detergent fiber, %DM	42.3	41.7	40.3	37.9	38.6
Acid detergent fiber, %DM	32.0	32.4	29.5	29.2	27.9
Ash, %DM	8.1	7.2	7.2	7.1	7.2
Gross energy, kcal/kg DM	4578.0	5325.0	5566.8	5325.6	5346.8
HCN, mg/kg	0.0	33.5	19.1	7.0	11.2
Total fatty acid, %DM	1.9	8.8	8.7	8.4	8.4
Fatty acid, % of total fatty acid
C12:0	25.8	0.5	0.4	0.3	0.5
C14:0	9.4	0.3	0.2	0.1	0.3
C16:0	18.3	10.2	10.2	10.1	10.8
C16:1 cis-9	0.0	0.3	0.3	0.2	0.3
C17:0	0.0	0.1	0.1	0.1	0.1
C18:0	4.0	6.5	7.0	6.7	7.1
C18:1 cis-9 + tran-9	25.7	23.8	24.1	23.9	25.0
C18:2 cis-9,12 + tran-9,12	15.2	38.0	38.1	39.0	37.6
C18:3 cis-9,12,15	1.6	19.6	19.1	19.1	17.7
C20:0	0.0	0.3	0.3	0.3	0.3
C20:1 cis-11	0.0	0.1	0.1	0.1	0.1
C22:1 cis-13	0.0	0.2	0.3	0.2	0.2

 

2.6. In Vitro Gas Production and Fermentation Characteristics

Specify the choice of interpolating the data obtained from the measurement of gas production, according to Ørskov and McDonald and not according to what is indicated by Groot et al. (1996) specifically for gas production.

- To describe the kinetics of gas production data, the exponential model of Ørskov and McDonald (1979) is widely used in ruminant feed evaluation. The three-phasic model of Groot et al. (1996) performs better than the model of Ørskov and McDonald (1979) based on first-order kinetics. However, in this study, we focus on the effects of the heating method of rubber seed kernel on the soluble fraction (a) and insoluble fraction (b) of their seed in the rumen. So, we selected the model of Ørskov and McDonald (1979) use in this study.

 

3.3. In vitro rumen fermentation and microbial population

Data relating to the rumen population are reported, but in no part of the text, and in particular in the materials and methods, are the methods of evaluation and counting of these populations mentioned

-L152-153: Already added to “The total direct counts of bacteria and protozoa were assessed using a hemocytometer (Boeco, Hamburg, Germany) described by Galyean [32]., please see in text.

 

4. Discussion

The paragraph seems more concentrated on reporting what is in the bibliography than commenting on the data obtained, only in some points.

Please revise the paragraph accordingly.

For example, nothing is reported on the fact that the immediately soluble fraction (a) is always negative. Demonstrating the fact that it would have been better to use another interpolation method, as the one used was born more for the study of rumen degradation kinetics of proteins than for the fermentescibilty of carbohydrates

-L232-238: Already added to “The mathematical model of Ørskov and McDonald [29] is commonly used to describe the kinetics of gas production in feedstuffs and ruminant diets [40]. It is based on first-order kinetics and assumes a constant fractional rate of fermentation [41]. Hence, the immediately soluble fraction is negative, as was found in previous studies [42-45]. Similarly, the immediately soluble fraction was negative (-4.8 to -6.9) for the dietary treatments in the current study. When the intent was to evaluate the lag time, the first-order exponential model underestimated the actual results [46]., please see in text.

 

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

The manuscript has been sufficiently improved to warrant publication in Fermentation.