Assessing the influence of feeding olive leaves on the productivity and economic viability of growing Awassi lambs

Abstract

The goal was to assess the influence of feeding olive leaves (OL) as a roughage source on nutrient intake, nutrient digestibility, N balance, growth performance and carcass characteristics of growing Awassi lambs. Twenty-four male lambs (initial body weight (BW) = 16.82 ± 0.998 kg; age = 70 ± 1.25 days) were randomly assigned to two isonitrogenous diets; OL at 0 (CON) or 150 (OL150) g/kg of dietary dry matter (DM). Diets were fed ad libitum for a period of 60 days after 7 days of adaptation. Feed intake and refusals were recorded daily. Body weights were recorded at the beginning of the study and at biweekly intervals thereafter. Intake of DM and crude protein was similar (P ≥ 0.05) between the two diets. Feeding OL decreased (P ≤ 0.01) intake of neutral detergent fiber and acid detergent fiber whereas it increased (P = 0.001) intake of ether extract compared with the CON diet. No differences (P ≥ 0.05) were observed in the final BW, average daily gain, and total gain between diets. However, the cost of gain was lower (P = 0.05) in lambs fed the OL diet versus the CON diet. None of the carcass characteristics nor meat quality parameters differed between the two diets. In summary, feeding olive leaves at 150 g/kg did not influence growth performance and carcass characteristics and meat quality but improved the economic value of using such products in diets of growing lambs. In addition, the use of this product has a positive impact on reducing environmental pollution.

Keywords:

• Awassi lambs
• cost of gain
• carcass characteristics
• olive leaves

Acknowledgments

Appreciation is expressed to Eng. Tha’er Meqdadi and Eng. Majdi Abu Ishmais for assistance in conducting this experiment and laboratory analyses. The authors wish to thank the Deanship of Scientific Research JUST for the financial support of this project (#: 515/2022).

Disclosure statement

No potential conflict of interest was reported by the author(s).

Authors’ contributions

The corresponding author BSO contributed to the conceptualization and methodology; format analysis contributed to the investigation and writing of the original draft; MGT, writing, review and editing. All authors read and approved the final manuscript

Availability of data and materials

The authors confirm that the data supporting the findings of this study are available within the article.

Ethics approval and consent to participate

All experimental procedures were approved by the JUST Animal Care and Use Committee (#: 16/04/12/459B; 23/08/2022)

List of abbreviations

ADF	=	acid detergent fiber;
ADG	=	average daily gain;
ARTU	=	Agricultural Research and Training Unit;
CL	=	cocking loss;
BW	=	body weight;
CP	=	crude protein;
DM	=	dry matter;
EE	=	ether extract;
FCR	=	feed conversion ratio;
JUST	=	Jordan University of Science and Technology;
OL	=	olive leaves;
NDF	=	neutral detergent fiber;
WHC	=	water holding capacity.

Correction

This article has been corrected with minor changes. These changes do not impact the academic content of the article.

Additional information

Funding

This work was supported by Jordan University of Science and Technology (515/2022).