# Impact of Fe-Zn Biofortified Alfalfa on Growth Performance, Feed Efficiency, and Mineral Deposition in Guinea Pigs (Cavia porcellus) Under Smallholder Production Systems

## TL;DR

Feeding guinea pigs with iron and zinc-enriched alfalfa improves their feed efficiency without harming growth or meat quality.

## Contribution

This study demonstrates that biofortified alfalfa can enhance feed efficiency in guinea pigs without adverse effects.

## Key findings

- Guinea pigs fed enriched alfalfa had better feed efficiency with lower feed conversion ratios.
- Meat quality and mineral content remained stable despite dietary changes.
- Biofortified alfalfa shows potential for sustainable smallholder guinea pig production.

## Abstract

Within most smallholder farming systems, animal protein sources such as guinea pigs play a significant role in the animal protein intake, and their development and feed consumption can be restricted due to low mineral levels in the traditional feeds. Zinc and iron are very vital minerals in the growth, health, and productivity of animals, but they are mostly lacking in forage crops. This experiment determined the effectiveness of animal performance under a smallholder-type environment of feeding the guinea pigs with a grown alfalfa that had been enriched with zinc and iron. Young guinea pigs were fed on the four types of alfalfa that were grown with and without mineral enhancement. Our measurements were of meat growth, feed intake, feed efficiency, and mineral content. Guinea pigs fed the enriched alfalfa consumed less feed to gain weight, and yet they grew normally, and their meat was of normal quality. There were minimal differences between the males and females, and the trace levels of the mineral in the meat were not significantly altered, which was a sign that it was controlled naturally in the animals. Comprehensively, zinc-iron bio-fortified alfalfa appears to be a viable approach to feeding in the production of guinea pigs, as it does not have any adverse impact on the performance of the animals. This would assist the smallholder farmers to minimize the cost of feeding and enhance the sustainability of guinea pig production systems.

This study examined the effects of zinc–iron (Zn–Fe) biofortified alfalfa on mineral deposition, growth performance, feed efficiency, and selected meat-quality traits in guinea pigs (Cavia porcellus). Four alfalfa cultivars (Cuf101, Moapa69, California55, and Yaragua) were cultivated under two fertilization levels (0–0 and 2–2 kg ha−1 Zn–Fe). Biofortification increased forage Zn concentrations from 26.8 to 36.4 mg kg−1 to as high as 325.8 mg kg−1, and Fe concentrations from 139.7 to 425.0 mg kg−1 to 450.1 mg kg−1. A total of 48 weaned guinea pigs (initial body weight 0.30 ± 0.01 kg) were allocated to a randomized multi-factorial feeding trial. Growth performance, feed intake, feed conversion ratio (FCR), and tissue mineral concentrations were evaluated over a 35–50 day period and analyzed using a multi-factorial ANOVA within a General Linear Model framework. Dietary biofortification resulted in a significant improvement in feed efficiency, with FCR decreasing from 6.3 in the control diet to 5.8 in the enriched diet, and the lowest FCR was observed in animals fed the California55 cultivar (5.1). No statistically significant sex effect was detected for live weight gain, although males showed higher total weight gain (248.7 g) than females (187.8 g). Tissue Zn (≈20.7 mg kg−1) and Fe (≈10.2 mg kg−1) concentrations in meat were only marginally affected by diet, suggesting strong physiological regulation of mineral deposition. Multivariate analyses indicated that the enriched diet produced more homogeneous meat-quality profiles and reduced inter-animal variability. Overall, Zn–Fe biofortified alfalfa improved feed efficiency without compromising growth performance or meat quality, indicating potential relevance for smallholder guinea pig production systems. However, given the limited sample size per factorial cell, the findings should be interpreted with caution and considered exploratory, warranting confirmation in larger, adequately powered studies.