| Livestock Research for Rural Development 35 (6) 2023 | LRRD Search | LRRD Misssion | Guide for preparation of papers | LRRD Newsletter | Citation of this paper |
In the Philippines, climatic unpredictability has been one of the main factors causing fluctuations in forage production; as a result, an efficient feed preservation strategy must be used. This study assessed the effect of various levels of L. plantarum as Napier silage inoculant on sheep's feed intake and growth performance. Using a Completely Randomized Design (CRD) set-up, a total of thirty (30) growing female sheep were randomly distributed to five (5) treatments and replicated six (6) times with one (1) animal per replication. The treatments were: Lp0 (control), Lp1 (Napier silage+1% L. plantarum), Lp2 (Napier silage+2% L. plantarum), Lp3 (Napier silage+3 % L. plantarum) and Lp4 (Napier silage+4% L. plantarum). Despite insignificant differences (p>0.05) in treatments on feed intake, a slight improvement was shown in the total feed intake of 3% L. plantarum. A slight reduction (p>0.05) of dry matter, organic matter, and crude protein intakes was observed in silages with 1% and 2% L. plantarum. A significant decrease (p<0.05) in NDFI was observed when the level of L. plantarum added increased. The most significant (p<0.05) increase in the growth rate and feed conversion efficiency was observed at the 2% level of L. plantarum. The results showed that incorporating L. plantarum at 2% different level improved the overall growth performance of sheep.
Keywords: body weight gain, elephant grass, feed conversion ratio, probiotics
Climatic variability has been one of the principal sources of fluctuations in forage production in the Philippines, particularly in the semi-arid, flood-prone parts of the country. Therefore, feed preservation strategies must be practised. One of which is silage making. Silage is a form of preserved pasture. Silage making is an important initiative for farmers to feed livestock animals during times forage supply is not good, such as the El Niņo season. Silage production is less reliant on the weather than hay production. Additionally, silage conservation does not need to be as labour-intensive as daily grass cutting for ruminants (Wong 2000). One of the most common forages for silage making is the Napier grass or the elephant grass (Pennisetum purpureum Sch.). In the Philippines, it has shown itself well adapted to climate and soil and is more drought-resistant than any other forage plant introduced (Webster 1920).
Probiotics are one of the most recent innovations in silage producing techniques. Probiotics are living bacteria that enhance the gut microbial balance of the host animal (Parker 2001). L. plantarum is one of the most often used bacterial inoculants in pasture ensiling studies (Fiya 2003; Arasu et al 2014). The L. plantarum improved the quality of silage (Zhe et al 2022). However, no reports were found on the specific level of L. plantarum as silage inoculant on Napier silage that will result in efficient growth performance. Therefore, this study was undertaken to assess the impact of various levels of L. plantarum as Napier silage inoculant on sheep's feed intake and growth performance.
The Napier grass (Pennisetum purpureum Sch.) was harvested at around 3-4 weeks of regrowth with a DM content of 28%. The harvested Napier grass was chopped using a mechanical chopper. The chopped Napier grass was divided into five 50 kg container drums. Each container drum was labeled based on the following treatments: Lp0 control (no probiotic added); Lp1 (Napier silage + 1% L. plantarum), Lp2 (Napier silage + 2% L. plantarum), Lp3 (Napier silage + 3% L. plantarum) and Lp4 (Napier silage + 4% L. plantarum). To inoculate the Napier forages, the Lactobacillus plantarum inoculation agents were first diluted in 200 mL of sterilised distilled water, then sprayed equally across each pile and carefully mixed. The experimental silages were stored tightly. The silage samples were stored at room temperature at about 27 to 30 degrees Celsius. The experimental forages were packed tightly in a silage container drums. After 21 days of anaerobic fermentation, the drum was opened for a feeding trial.
The Lactobacillus plantarum inoculant was tested for the presence of microorganisms before use. Using nutritional agar (NA) for microorganisms and potato dextrose agar, or PDA, for molds, dilution plating was used to estimate the probiotic concentration. A total of nine (9) cc of sterilized water were supplied to a test tube in order to reduce the concentration of a one (1) millilitre sample to 107. Dilutions were pipetted into sterile Petri dishes, starting with 1 ml in each dilution tube. A 10-12 ml medium, cooled to about 45°C, was added to each plate and gently mixed. Six replicate plates were made for each dilution. The plates were incubated at room temperature in the laboratory. Colony counting was made after 3-4 days incubated for bacteria. The cultural characteristics of the microbial colonies were described. Microscopic examination was also conducted to study morphology of microorganisms. Gram staining was done for the isolates.
Thirty female Dorper sheep weighing between 15-19 kg were utilized in the study. The animals used in the experiments were kept in separate cages so that they wouldn't re-infect each other or the pastures or soil after receiving treatment. Prior to housing the animals, the cages were given a thorough cleaning and disinfection. The sheep were dewormed before the study. Using a Completely Randomized Design (CRD) set-up, a total of thirty (30) growing female sheep were randomly distributed to five (5) treatments and replicated six (6) times with one (1) animal per replication. The sheep were housed individually in the metabolic cages and cleaned three (3) days before placing the animal. A ration consisting of a base diet of Napier silage and different concentrations of L. plantarum was given to the sheep in every treatment twice daily. During the course of the experiment, a constant supply of potable water was provided.
The sheep had 14 days of conditioning before the experiment began. Strict adherence was made to the conventional protocol for the gradual transition from their regular ration to experimental diet.
The feeding trial lasted for two months or eight (8) weeks (see Table 1). The voluntary feed intake of the experimental sheep were computed to 3 percent of BW expressed on a DM basis such that each forage was given 1.5 percent of BW divided in two equal feedings in the morning and afternoon (every 7:00AM & 3:00 PM) and other management practices were ensured to be similar to all treatments all throughout the duration of the study. The fresh drinking water was also ensured to be available at all times.
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Table 1. Schedule of activities |
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Day |
Activity |
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|
1-14 |
Shifting gradually from the initial diet to the treatment diets test feeding. Feeding the basic diet in moderation (Silage). |
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|
14-60 |
Feed was given at 3 % of body weight, dry Matter Basis, and initial weight measured on day 8. Every 14 days monitoring of weight changes |
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|
31-36 |
Shifting gradually from the initial diet to the treatment diets test feeding. Feeding the basic diet in moderation (Silage) |
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|
60 |
Measurement of the final weight of the animals |
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Fresh Napier, Feed (Silage), and faecal samples were examined at the Department of Animal Science, College of Agriculture and Food Science, Visca, Baybay City, Leyte, for the dry matter (DM), organic matter (OM), crude protein (CP), and neutral detergent fibre (NDF) contents using the AOAC 1990 methods.
Bi-weekly Cumulative Voluntary Feed intake, (CVFI) - is calculated by subtracting the feed rejected out of the feed given as the entire quantity of feed that the sheep freely consume every two weeks.
CVFI = Σ(Feed Given – Feed Refused)
Nutrient Intake-was measured by determining the total feed intake of the sheep and the total feed refused by the sheep. This was computed using the equation below:
Nutrient intake (g)= [(Feed given x % nutrient of given)-(feed refused x % of nutrient refused)]
Whereas the nutrients were: DM, OM, CP, and NDF
Nutrient intake (as %body weight)-account in the differences in body size affecting feed intake
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Whereas the nutrients were: DM, OM, CP, and NDF
Feed conversion ratio - was calculated as the daily nutrient intake in the feed given to the animal divided by its average daily gain
 |
Whereas the nutrients were: DM, OM, CP, and NDF
Data gathered were analyzed by using analysis of variance (ANOVA) techniques through the using General Linear Model (GLM) procedures of the Statistical Package for Social Science (SPSS) Version 25. Treatment means were compared using Tukey’s Honestly Significant Difference (HSD) Test.
The nutrient content of Napier silage at different levels of L. plantarum as an inoculant is shown in Table 2. The term "proximate" describes the process of identifying a feed's significant constituents, which is used to determine whether a feed is within the bounds of its typical composition. Crude protein (CP), organic matter (OM), neutral detergent fiber, and dry matter (DM) were the nutrients identified. (NDF).
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Table 2. Proximate analysis of Napier (Pennisetum purpureum sch.) silage with varying levels of L. plantarum as inoculant |
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|
Nutrient |
L. plantarum |
||||
|
0 |
1 |
2 |
3 |
4 |
|
|
DM, % |
20.8 |
23.4 |
20.6 |
21.9 |
19.8 |
|
OM, % |
84.9 |
84.2 |
83 |
81.5 |
80.4 |
|
CPI, % |
8.12 |
8.23 |
8.38 |
8.39 |
8.51 |
|
NDFI, % |
51.9 |
41.9 |
33.9 |
32.2 |
32.1 |
|
DM=dry matter; OM=organic matter, CP=crude protein, NDF=neutral detergent fiber 0=Control; 1=Napier silage + 1% L. plantarum; 2=Napier silage + 2% L. plantarum; 3=Napier silage + 3% L. plantarum; 4=Napier silage + 4% L. plantarum |
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All treatments' DM and CP content were almost similar, but a slight improvement in the CP content in the inclusion of L. plantarum on the Napier silage was shown in Table 2. Moreover, a decreasing trend of OM and NDF content was observed as the L. plantarum increased. The ensilage process' acid hydrolysis of easier to digest plant cells accounts for the reduced NDF found in Napier silage inoculated containing L. plantarum (McDonald et al 1991).
Data on the cumulative feed intake in fresh weight basis of sheep fed with Napier (Pennisetum purpureum Sch.) silage supplemented with various levels of L. plantarum is shown in Table 3. The nutrient intake by weight, the basis is presented in Table 3. Despite insignificant differences (p>0.05) in treatments on feed intake, a slight improvement was shown in the total feed intake of Lp3 (Napier silage+3% L. plantarum). Generally, an increasing trend was observed from all treatments from weeks 2-8. A slight reduction of DMI, OMI and CPI was observed in Lp1 (Napier silage+3% L. plantarum) and Lp2 (Napier silage+2% L. plantarum), as shown in Table 4. A significant decrease (p<0.05) in terms of NDFI was observed when the level of L. plantarum added as Napier silage inoculant increase.
Curvilinear responses for DMI (g/d) NDFI (g/d) were presented in Figures 1 and 2, respectively. The mechanism underlying the curvilinear relationship for DMI were uncertain, it may result from the interactions between the gut microbiota, host physiology, and feed intake control L. plantarum may modify the composition of the gut microbiota and enhance nutrient absorption at small probiotic dosage levels, improving DMI. Probiotics can improve the rumen's microbial activity, which increases the synthesis of fibrolytic enzymes that break down NDF constituents (Wallace 2009). This causes the rumen's NDF concentration to drop and the intake of sheep to decrease (see Figure 2). The work by Kleinshmit and Kung (2006), which showed a reduction in the animals given silages infused with L. buchneri, which generally had acetic acid concentrations of about 40 g/kg, supported the decrease of DMI at lower concentrations of L. plantarum. The higher DM content and greater nutritional value of the infected silage are the most likely causes of this reaction (lower NDF content).
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Table 3. Cumulative feed intake (kg) in fresh weight basis of sheep fed with Napier (Pennisetum purpureumsch.) silage with varying levels of L. plantarum as inoculant |
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|
Week |
L. plantarum , % |
p |
||||
|
0 |
1 |
2 |
3 |
4 |
||
|
2 |
35 |
29.2 |
31.5 |
36.2 |
35.4 |
0.39 |
|
4 |
38.3 |
31.6 |
32.3 |
42.3 |
40.9 |
0.08 |
|
6 |
41.9 |
34.2 |
43 |
42.3 |
41.4 |
0.17 |
|
8 |
42.3 |
37.9 |
37.3 |
43.7 |
42.0 |
0.30 |
|
Total feed intake |
159.5 |
133 |
134.2 |
160.8 |
156.3 |
0.07 |
|
0=Control; 1=Napier silage + 1% L. plantarum; 2=Napier
silage + 2% L. plantarum; 3=Napier silage + 3% L. plantarum;
4=Napier silage + 4% L. plantarum |
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Table 4. Nutrient intake of sheep fed with Napier (Pennisetum purpureum sch.) silage with varying levels of L. plantarum as inoculant |
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|
Intake |
L. plantarum, % |
p |
||||
|
0 |
1 |
2 |
3 |
4 |
||
|
DMI (g/d) |
552.1 |
495.8 |
460 |
588 |
514.9 |
0.54 |
|
OMI (g/d) |
2257.2 |
1867.0 |
1856.2 |
2185.3 |
2095.5 |
0.06 |
|
CPI (g/d) |
215.9 |
182.4 |
187.4 |
224.9 |
221.7 |
0.42 |
|
NDFI (g/d) |
1378.4 a |
927.8 b |
757.5 c |
863.5 b |
836.2 bc |
0.02 |
|
DMI (%BW) |
2.91 |
1.29 |
2.49 |
3.10 |
2.6 |
0.65 |
|
OMI (%BW) |
11.91 a |
4.86 b |
5.86 b |
11.5 a |
10.4 a |
0.03 |
|
CPI (%BW) |
1.14 |
0.48 |
0.60 |
1.19 |
1.10 |
0.52 |
|
NDFI (%BW) |
7.27 a |
2.42 c |
2.39 c |
4.56 b |
4.15 b |
0.04 |
|
DMI=dry matter intake; OMI=organic matter intake, CPI=crude protein intake, NDFI=neutral detergent fiber intake 0=Control; 1=Napier silage + 1% L. plantarum; 2=Napier silage + 2% L. plantarum; 3=Napier silage + 3% L. plantarum; 4=Napier silage + 4% L. plantarum One-way Analysis of Variance; p<0.05=significant, p>0.05=not significant |
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 |  |
| Figure 1. Curvilinear trend
on the DMI (g/d) of sheep fed with Napier silage with varying levels of L. plantarum as inoculant |
Figure 2. Curvilinear trend on the NDFI (g/d)
of sheep fed with Napier silage with varying levels of L. plantarum as inoculant |
Palatability is one of the factors that influence feed intake on a fresh basis. The more palatable the forage is, the higher the feed intake can be observed. A preferred response to the eaten raw materials or feed for animals is palatability (Grovum 2008). Feed palatability refers to the properties of feeds that encourage animals' olfactory, gustatory, and tactile receptors to accept them (Scharenberg et al 2007). Taste, smell, and texture of the feed components were likely factors in the palatability of feedstuffs, especially silage. This outcome was consistent with a prior study, which found that silage samples treated with probiotic were digestible better than silages not treated with probiotics (Sofyan et al 2007). The aromatic flavour that developed during ensilage was linked to the enhanced palatability of the infected silage. Through the participation of enzymes in the process for the synthesis of aromatic compounds/flavoring substances in silage, this volatile molecule has added to fragrance creation in silage. According to Carrau et al (2008), probiotics can be added to fermentation grape juice products to produce aromatic compounds, such as esters, alcohols, acids, and lactones, which are used as flavouring agents.
Table 5 provides an overview of the growth results of sheep fed Napier silage with various concentrations of L. plantarum used as an inoculant. Total weight gain (TWG), average daily gain (ADG), and feed conversion ratio based on dry matter (DM), organic matter (OM), crude protein (CP), and neutral detergent fibre were the growth performance metrics. (NDF). In general, when sheep were given silage treated with L. plantarum, the growth indicators were improved. Lp2 (Napier silage + 2% L. plantarum) had the largest weight increase and the best feed conversion ratio, with significant differences (p<0.05) seen in the overall weight gain, average daily gain, and FCR for DM, OM, and NDF.
LP2 (Napier silage + 2% L. plantarum) have shown the best growth performance and feed conversion ratio, as presented in the response curve in Figure 3 and 4. While levels of L. plantarum are unlikely to reduce feed ADG and feed conversion efficiency (FCR) in ruminants, excessive supplementation or addition (>2%) may disturb the balance of the rumen microbiota, resulting in decreased growth and efficiency. Lactic acid buildup caused by Lactobacillus species overgrowth can lower rumen pH, inhibiting the growth of fiber-digesting microbes and further reducing fiber digestion and VFA synthesis (El-tawab et al 2016).This can lower nutrient availability and utilization, harming ruminant growth performance.
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Table 5. Total weight gain (TWG), average daily gain (ADG) and feed conversion ratio (FCR) of Napier (Pennisetum purpureumsch.) silage with varying levels of L. plantarum as inoculant |
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|
Parameters |
L. plantarum |
p |
||||
|
0 |
1 |
2 |
3 |
4 |
||
|
TWG,g |
1975 bc |
2100 b |
3350 a |
2400 b |
2300 b |
0.04 |
|
ADG, g |
32.9 b |
35 b |
55.8 a |
40 b |
38.3 b |
0.04 |
|
FCR, DM |
16.8 b |
14.2 bc |
8.2 a |
14.7 bc |
13.4 c |
0.03 |
|
FCR, OM |
68.6 b |
53.3 c |
33.3 a |
54.6 c |
54.7 c |
0.02 |
|
FCR, CP |
6.6 |
5.2 |
3.4 |
5.5 |
5.8 |
0.54 |
|
FCR, NDF |
41.9 a |
26.5 b |
13.6 c |
21.9 b |
21.8 b |
<0.01 |
| TWG=total weight gain; ADG=average daily gain; FCR=feed conversion ratio 0=Control; 1=Napier silage + 1% L. plantarum; 2=Napier silage + 2% L. plantarum; 3=Napier silage + 3% L. plantarum; 4=Napier silage + 4% L. plantarum One-way Analysis of Variance; p<0.05=significant, p>0.05=not significant | ||||||
 |  |
| Figure 3. Curvilinear trend on the ADG in
grams of sheep fed with Napier silage with varying levels of L. plantarum as inoculant |
Figure 4. Curvilinear trend on the FCR, DM
in grams of sheep fed with Napier silage with varying levels of L. plantarum as inoculan |
AOAC 1990 Official Methods of Analysis (15Th ed.). Association of Official Analytical Chemists. Arlington: AOAC.
Arasu M V Jung M W Kim D H Ilavenil S Jane M Park H S Al-Dhabi N A Jeon B T Choi KC 2014 Enhancing Nutritional Quality of Silage by Fermentation with Lactobacillus plantarum . Indian J Microbiol. 54(4):396-402. doi: 10.1007/s12088-014-0473-9
Carrau F M K Medina L Farina E Boido P A Henschke and Dellacassa E 2008 Production of fermentation aroma compounds by Saccharomyces cerevisiae wine yeasts: effects of yeast assimilable nitrogen on two model strains. FEMS Yeast Res. 8: 1196- 1207
El-Tawab A B D Youssef M M Bakr M I Fthenakis G C and Giadinis, N D 2016 Role of probiotics in nutrition and health of small ruminants. Polish Journal of Veterinary Sciences, 19(4), 893–906. doi:10.1515/pjvs-2016-0114
Filya I 2003 The effect of Lactobacillus buchneri and Lactobacillus plantarum on the fermentation, aerobic stability, and ruminal degradability of low dry matter corn and sorghum silages. Journal of dairy science, 86(11), 3575–3581. https://doi.org/10.3168/jds.S0022-0302(03)73963-0
Grovum W L 2008 Appetite, palatability and control of feed intake. In: The Ruminant Animal Digestive Physiology and Nutrition. D. C. Church (Ed). A Reston Book Prentice Hall, Englewood Cliffs, New Jersey. pp. 202-216.
Guo X S Ke W C Ding W R Ding L M Xu D M and Wang W W 2018 Profiling of metabolome and bacterial community dynamics in ensiled Medicago sativa inoculated without or with Lactobacillus plantarum or Lactobacillus buchneri. Sci. Rep. 6:28358. doi: 10.1038/srep28358
Kleinschmit D H and Kung L J R 2006 A meta-analysis of the effects of Lactobacillus buchneri on the fermentation and aerobic stability of corn and grass and small-grain silages. Journal of Dairy Science, 89, 4005–4013.
McDonald P Henderson N and Herson S 1991 The Biochemistry of Silage. Chalcombe Publications, USA
Scharenberg Y Arrigo Y Gutzwiller A Soliva C R Wyss Kreuzer M and Dohme F 2007 Palatability in sheep and in vitro nutritional value of dried and ensiled sainfoin (Onobrychis viciifolia) birdsfoot trefoil (Lotus corniculatus), and chicory (Cichorium intybus). Arch. Anim. Nutr. 61: 481-496.
Sofyan A Herdian H Febrisiantosa A and Julendra H 2007 The palatability of complete feed silage treated by semi-aerobic inoculants. Proceeding of National Seminar “Asosiasi Ahli Nutrisi dan Pakan Indonesia (AINI) VI”. Faculty of Animal Sciences, UGM-Yogyakarta, 26-27 July 2007. Pp. 416-421
Wallace R J 2004 Ruminal microbial metabolism of peptides and amino acids. Journal of Nutrition, 134(3), 657S-661S.
Webster P J 1920 Napier Grass: A Promising New Forage Plant for the Philippines. Philippine Agricultural Review 1920 Vol.13 No.4 pp.353-354 pp.