# Influence of substituting 25% alfalfa hay with Panicum maximum cv. Mombasa with or without spirulina supplementation on the productive performance of fattening Barki lambs

## TL;DR

Replacing part of alfalfa hay with Panicum hay and adding Spirulina improves lamb growth and health in salty environments.

## Contribution

The study introduces a novel combination of salt-tolerant forage and Spirulina supplementation to enhance lamb performance in saline regions.

## Key findings

- Substituting 25% alfalfa with Panicum hay reduced feed intake and ruminal parameters but improved digestibility and growth.
- Spirulina supplementation at 2 mg/g significantly enhanced feed intake, digestibility, blood parameters, and growth rates in lambs.
- Alfalfa-based diets outperformed Panicum-based ones, but Panicum with Spirulina offers viable performance in saline areas.

## Abstract

Combining salt-tolerant forages with conventional forage can provide an alternative solution for enhancing livestock production in areas affected by salt. This study aimed to evaluate the effects of substituting 25% of alfalfa hay with Panicum maximum hay, with or without Spirulina (2 mg/g), on the feed intake, digestibility, ruminal fermentation, blood parameters, and growth rate of Barki lambs. Thirty-two lambs, aged 3 months, with an average initial body weight of 21.62 kg (± 3.23), were used in the fattening experiment. The animals were weighed and then randomly assigned to four groups, eight lambs each. The experimental diets were isonitrogenous and isocaloric, containing 40% forage. Alfalfa was partially replaced with Panicum hay, with T1 and T2 having 0% Panicum and T3 and T4 containing 25%. Additionally, animals in T2 and T4 received Spirulina supplementation at 2 mg/g. The substitution of 25% of alfalfa hay with Panicum resulted in a significant reduction (p < 0.0001) in feed intake, TVFA, and NH3 levels. Lambs-fed diets containing 40% alfalfa hay demonstrated the highest nutrient digestibility (CP 790.2 vs. 765.85, EE 817.7 vs. 758.6, CF 632.90 vs. 551.60), nutritive value (TDN 741.90 vs. 711.70), blood parameters (TP 6.44 vs. 5.97, Alb 3.5 vs. 3.27), and growth rates (FBW 49.75 vs. 46.06, TG 28.12 vs. 24.44, ADG 234.37 vs. 203.) compared to those receiving diets with 10% Panicum. Supplementation with Spirulina at 2 mg/g significantly increased feed intake, TVFA (7.87 vs. 6.84), NH3(18.10 vs. 16.78) levels in the rumen, digestibility (CP 746.38 vs. 710.61, EE 812.4 vs. 763.9, CF 622.10 vs. 562.40), nutritive value (TDN 736.50 vs. 717.10), blood parameters (TP 6.34 vs. 6.07, Alb 3.49 vs. 3.32), and growth rates (FBW 49.16 vs. 46.65, TG 27.53 vs. 25.03, ADG 229.47 vs. 208.59)(p < 0.0001). In conclusion, incorporating 25% Panicum hay in lamb diets, particularly with Spirulina supplementation (2 mg/g), supports notable performance compared to pure alfalfa diets. While alfalfa remains superior, Panicum cultivation in saline lands is still viable. This combination is especially beneficial for lamb production in Egypt’s desert regions.

The online version contains supplementary material available at 10.1038/s41598-025-28525-1.