Chemical composition of tree leaves
The chemical composition of moringa, subabul and guava leaves are presented in Table 2.
Chemical composition of experimental diets
The chemical composition of concentrate mixtures containing twenty per cent (%) inclusion of moringa, subabul and guava leaves were similar for most of nutrients (Table 3), since only soya bean meal and de-oiled rice bran of control concentrate mixtures were partially replaced with moringa, subabul and guava leaves in experimental concentrate mixtures and rations were formulated to be iso-nitrogenous and iso-caloric.
Nutrient intake and digestibility
The mean intakes of DM, CP, DCP, TDN and ME were not affected (P>0.05) in ram lambs with inclusion of moringa, subabul and guava leaves either sole or in combination at 20% in concentrate mixtures and was comparable to control diet fed animals. The comparable nutrient intake can be attributed to the fact that the diets were iso-caloric and iso-nitrogenous and also inclusion levels of tree leaves were within the levels that were not adversely affecting the intakes. In accordance with our findings
Ramesh (2021) observed no effect on nutrient intake with inclusion of moringa and mulberry leaves up to 35% in concentrate mixture of lambs. Similarly dietary replacement of concentrate mixture with subabul leaves at 20% in chick pea straw based complete diets had no effect on the nutrient intake in rams (
Sushmitha, 2019). Contrary to our results,
Wankhede et al., (2022) reported higher (P<0.05) DCP and TDN intake in goat kids fed complete diets replacing wheat straw with moringa foliage at 25% compared to control which could be due to higher DM and CP intake in moringa supplemented group, in contrast to our study where intake of nutrient was similar in all dietary treatments.
The DM digestibility was higher (P<0.01) in MOR20, SBL20, MS20, MG20 dietary groups compared to control, while in GVL20 diet fed lambs the digestibility was comparable to control diet lambs (Table 4). The OM digestibility (OMD) improved (P<0.05) with inclusion of MOR20, MS20 and MG20 diets in concentrate mixture compared to CON. Whereas with inclusion of SBL20 and GVL20 diets no improvement in OMD was observed. Corroborating with our findings
Sanchez et al., (2006), Giang et al., (2016) reported improved DM and OM digestibility in cows with feeding of moringa and subabul leaves. In contrast to our findings,
Patra et al., (2006) reported that partial replacement (50%) of protein by
Leucaena leucocephala–
Morus alba–
Azadirachta indica (2:1:1) leaf meal mixture in goats had no effect on digestibility of DM and OM. Similarly,
Ali et al., (2018) had observed no effect on digestibilities of OM and DM in goats with replacement of cotton seed cake with moringa leaves, while
Montoya-Flores et al., (2020) reported that digestibility of OM in cross bred heifers decreased with increasing levels (12, 24 and 36%) of DMI of subabul leaves. These variations in results obtained from various studies may be attributed to differences in composition, inclusion levels of moringa and subabul tree leaves and other nutrients in diet.
In present study, the digestibility of CP was higher (P<0.01) with inclusion of moringa, subabul and guava leaves at 20% in concentrate mixture of lambs compared to control (Table 4). Corroborating with the observations of
Sanchez et al., (2006), Gebregiorgis et al., (2012), Ramesh (2021) where CP digestibility increased with supplementation of moringa leaves. Similarly,
Montoya-Flores et al., (2020) reported increased CP digestibility in heifers with inclusion of subabul leaves at 12 and 24% of DM compared to control. The improved CP digestibility observed in present study could be attributed to tannin content in tree leaves as tannins binds to dietary protein, thus protecting it from rumen degradation and increasing protein flow to the small intestine of the host
(Salem et al., 2013). Contrary to results of our study,
Sushmitha (2019) reported no effect on CP digestibility with inclusion of subabul leaves in concentrate mixture at 20% in chick pea straw based complete diet of rams.
In general, the inclusion of moringa, subabul and guava leaves at 20% in concentrate mixtures improved (P<0.01) the digestibility of CF and fiber fractions (NDF, ADF, hemicellulose and cellulose) in the diet and digestibility of these was either comparable or higher than the control group (Table 4). The higher fiber digestibility in tree leaves fed lambs could be due to better utilization of CP (Table 4) and was in synchrony with soluble carbohydrate availability
(Sanchez et al., 2006). Similarly,
Zaher et al., (2020), Ramesh (2021) reported higher fibre digestibilities with inclusion of moringa and mulberry leaves in concentrate mixtures of rams. In contrast to the present study no effect on fibre fractions digestibility was reported by many workers with replacement of concentrate mixture with moringa at 25, 50 and 75% in sheep
(Gebru et al., 2017), replacement of cotton seed cake with moringa leaves in goats
(Ali et al., 2018). Similarly,
Sushmitha (2019) reported no effect on digestibility of fiber fractions in lambs with inclusion of subabul leaves in concentrate mixture at 20% in chick pea straw based complete feed diets.
The EE digestibility was significantly (P<0.01) lower in tree leaves leaves included diets compared to control fed lambs. The lower EE digestibility with inclusion of tree leaves could be attributed to differences in fat composition and tree leaves may contain more ether soluble components than true fat compared to soya bean meal and de-oiled rice bran in concentrate mixture. In accordance with our findings,
Ramesh (2021) reported decreased (P<0.05) EE digestibility in lambs with inclusion of moringa and mulberry leaves in concentrate mixture at 30 and 35%. In contrary,
Kholif et al., (2015); Ali et al., (2018); Sushmitha (2019);
Wankhede et al., (2022) reported no effect on EE digestibility with dietary inclusion of tree leaves. The digestibility of NFE increased (P<0.01) with inclusion of moringa, subabul and guava leaves either sole or in combination at 20% in concentrate mixtures in the diet and digestibility of these was either comparable or higher than the control group. The higher NFE digestibility in lambs observed in present study with inclusion of moringa, subabul and guava leaves could be attributed to better synchrony in utilization of CP, fiber fractions and fermentable carbohydrates. In accordance to our findings
Asaolu et al., (2010), Ramesh (2021) reported increased NFE digestibility with inclusion of moringa leaves in diet. In contrary
Ali et al., (2018) Sushmitha (2019) and
Wankhede et al., (2022) reported no effect on NFE digestibility with inclusion of tree leaves in diet.
Nutritive value and plane of nutrition
The crude protein (CP) (%) in lambs fed diets containing different concentrate mixtures was comparable whereas DCP content of diets increased with inclusion of moringa either sole or in combination with subabul or guava at 20% and similar trend was observed with regard to TDN and ME content (Table 4). The comparable CP% among diets could be attributed to similar DM intake and iso-nitrogenous concentrate mixtures fed to lambs. The higher DCP,TDN and ME content observed with MOR20, MS20 and MG20 included diets could be attributed to higher CP, CF, NFE digestibility which resulted in high energy content in diets.
Nitrogen balance
The N intake (g/d), excretion through faeces and urine (g/d), total N excretion and total N balance (g/d) was comparable among the different dietary groups (Table 5). The lambs in all the dietary groups were on positive N balance. The positive N balance among the treatment groups is indication of energy and N supply much higher than the maintenance requirement of lambs. Corroborating with our results,
Sushmitha (2019);
Ramesh (2021) reported no effect on N retention and N balance in lambs fed with subabul and moringa leaves. Contrary to our results,
Sultana et al., (2015); Pineiro-Vazquez et al., (2017) reported significantly (P<0.05) higher N retention with feeding of moringa and subabul leaves.