Identification of macroalgae from the West Coast of Sulawesi and potential utilization as ruminant feed sources

The use of macroalgae as a ruminant feed is being widely developed due to its rich nutritional content and the presence of anti-methanogenic substances that may be able to reduce the formation of methane gas in ruminants. Macroalgae are cultivated and not cultivated; the species are diverse and grow in groups throughout Indonesian waters. This study aims to identify macro algae morphology that is easily found in the waters of the West Coast of Sulawesi and its potential use as a source of ruminant feed. Macro alga samples of cultivated and non-cultivated algae were collected from farmers and fishermen from the West Coast of Sulawesi, then continued with morphological identification. Several related articles and previous research obtained data regarding nutritional content using proximate analysis (protein, lipid and ash) and its potential use as a feed source. Research shows several macroalgae species that are easily found in the waters of the west coast of Sulawesi, namely macroalgae cultivated Gracilaria sp, Eucheuma denticulatum, Eucheuma cottonii, and Caulerpa sp. In contrast, the non-cultivated ones are Sargassum sp, Padina australis, Halymenia sp, Halimynea sp, and Caulerpa sp. Of the eight species, It is nutrient-rich and may be utilized as a source of feed for ruminants in the form of pure or extracts, but the proportion of macroalgae in the diet must be taken into account.


Introduction
The success of the livestock business can be determined by several factors, one of which is the availability of quality and sustainable feed.However, this factor is an obstacle to efforts to provide sustainable forage due to shifting land use, so the allocation of special land for forage production is increasingly limited [1].Feed independence is one indicator of the ability to produce quality and sustainable feed by utilizing the diversity of resources (natural, human, economic, and sociocultural/local wisdom) from within the country with dignity [2].
Macroalgae is one of the natural resources that could be used as animal feed.Various studies have been conducted on using seaweed or macroalgae as animal feed, and they are increasingly in demand, both whole and in extract form [3]. Due to their nutrition content and capacity to reduce enteric methane (CH4), macroalga can be used as a sustained feed component for ruminant production [4,5].Protein and dietary fiber content, relatively balanced amino acid profile, and rich content of minerals, vitamins, and bioactive compounds [6].Macroalgae are also ideal to be used as feed supplements because of their metabolite content (pigments, carotenoids, phlorotannin, unsaturated fats, agar gel, alginate), macro and micromineral content [7].
Macroalgae are a very diverse group of plants in seas worldwide [8].Indonesia has about 550 species of macroalgae [9].It is generally located in coastal areas and are available in a variety of sizes, shapes, IOP Publishing doi:10.1088/1755-1315/1292/1/012014 2 colors, and biochemical content.This group includes Phaeophyceae (brown seaweed), Rhodophyceae (red seaweed), and Chlorophyceae (green seaweed) [10].Based on the description above, research on identifying macroalgae from the west coast of Sulawesi and their potential use as a source of feed is considered important to be carried out.

Research location and timing
The study was carried out between February and May 2023.The study area was on the west coast of Sulawesi, specifically in the Barru, Takalar, Pinrang, Polewali Mandar, and Central Mamuju regencies.

Data collection technique
Macro algae samples were obtained by collecting several samples of cultivated and non-cultivated macro algae from farmers and fishermen located on the west coast of Sulawesi.Samples of macro algae cultivated in ponds are Gracilaria sp from Maros Regency, while macro algae cultivated in coastal areas are Eucheuma denticulatum from Polewali Mandar Regency, Eucheuma cottonii from Pinrang Regency, and Caulerpa sp from Takalar Regency.as for non-cultivated macro algae samples, namely Sargassum sp and Padina sp harvested in Barru Regency, Halymenia sp from Mamuju Tengah Regency while Caulerpa sp comes from Takalar Regency.All samples obtained were cleaned from the substrate, then morphologically identified with reference www.algabase.org.The variables observed were macromorphological characteristics of algae including leaves, stems, and roots.Meanwhile, data regarding nutritional content using proximate analysis (protein, lipid and ash) and its potential use as a feed source were obtained from several related articles and previous research.The findings of the research activities are presented descriptively.

Results and discussion
The results of macroalgae identification obtained from the west coast of Sulawesi have cultivated macroalgae consisting of Gracilaria sp, Eucheuma denticulatum, Eucheuma cottonii, and Caulerpa sp (Figure 1).Non-cultivated macroalgae are Sargassum sp, Padina sp, Halymenia sp, and Caulerpa sp (Figure 2).Of the eight species of macroalgae samples collected came from the class Rhodophyceae (red algae), namely Gracilaria sp, Eucheuma denticulatum, Eucheuma cottonii, and Halymenia sp.Class Chlorophyceae (green algae) is Caulerpa sp, while class Phaeophyceae (brown algae) is Sargassum sp, Padina sp.The morphological description of macroalgae species and nutrient content are listed in Table 1.

Gracilaria sp
Living by attaching oneself to a dense subtract (rock, coral, wood, etc.) grows to form clumps and forms branching.The tallus is cylindrical on the surface.There are nodules.The length of glacilaria sp is very partitive, about 10-20 cm per clump.It is generally yellowish-olive green.The average weight of one clump is 70 grams.

Eucheuma cottonii
It has a cylindrical and branched thallus.Irregular branching.The pointed or blunt end of the thallus is brown, purple, or yellow-green.The length of the thallus can reach 13 cm.It has irregular spin covering the thallus and its branch branches.Slippery surface.The appearance of the thallus varies from simple to complex shapes.The average weight per clump is 253 grams.Protein (2,05%), lipid (1,3%), and ash (3,7%).

Sargassum sp
It grows bush-shaped, attached to a coral substrate, dark brown and cream in color, and grows up to 25 cm in height; the main stem is rounded with a slightly rough surface, the shape of the leaves is wide, the edges of the leaves are Protein (45,63%), lipid (6,20%), and ash (8,28%).jagged and wavy with curved or tapered tips.Thallus length 10 -25 cm and fresh weight per clump 50 -150 grams.

Padina sp
It grows attached to coral rocks or hard subtracts.Tallus sheet-shaped, light brown, dark brown, tallus width 15 cm, rough surface, fresh weight per clump about 30 grams.

Halymenia sp
Life is attached to corals, maroon in color, and has a flattened, slippery, gelatinous thallus.It has intermittent branching of irregular alternating on both sides of the talus.The lower talus usually widens and tapers to the apex.The ends of the talus are branched, lush, and jagged.The average weight per clump varies around 150 grams-400 grams.The length of the tallus also varies and can reach 35 cm.Protein (14,13%), lipid (1,43%), and ash (17,12%).
Table 1 shows that the highest protein and lipid content is in the macroalgae type Sargassum sp, and the highest ash content is in the macroalgae type Halymenia sp.These results indicate that macroalgae's nutritional content differs depending on the type [11][12][13][14][15][16][17].Macroalgae have good opportunities to be utilized as a source of feed ingredients for ruminants.Using macroalgae in feed blended with other feed materials because if consumption alone can be detrimental to livestock.livestock.Seaweed is commonly used as a feed additive, as it is rich in beneficial metabolite compounds and a a natural source of macro and micro minerals [18].Sargassum sp., Gracilaria sp., and Eucheuma cottonii are common seaweeds cultivated in Indonesia.Commonly cultivated in Indonesia that have the same potential to be used as a source of macro minerals for dairy cattle [19].while the use of Gracilaria birdie in dairy goat rations can significantly respiration rate, rectal temp, and surface temp.This indicates Gracilaria birdiae can reduce stress in dairy goats against heat stress [20].Meanwhile, in another study, it was mentioned that adding Eucheuma cottonii as much as 4% in the ration decreased methane gas production although it was accompanied by a decrease in total VFA and partial VFA [21].
Green algae groups such as Caulerpa sp can be used as feed additives because they contain fiber, lipids, fatty acids, proteins, amino acids, vitamins, minerals, coloring agents, and antioxidants.The bioactive compounds contained are capable of being antibacterial, anti-inflammatory, and antioxidant [22].Brown seaweed such as Sargassum sp. can be used as alternative feed because it is abundant in some areas.This genus contains minerals, carbohydrates, vitamins, and essential amino acids [6].Goat diets containing elephant grass and brown seaweed produced the same rumen metabolic products and in vitro nutrient digestibility.Brown seaweed (Sargassum polycystum) can replace elephant grass in goat feed up to 37.5%.Because they contain dissolved carbohydrates and organic mineral sources, brown seaweed (Padina australis and Laminaria sp.) and red seaweed (Eucheuma cottonii and Gracilaria sp.) have the potential to be used as ruminant animal feed.However, it is thought that special attention must be paid to the amount of heavy metals to prevent toxic effects in ruminants [23].

Conclusion
A total of eight species of macroalgae samples collected from the west coast of Sulawesi came from the Rhodophyceae class (Gracilaria sp, Eucheuma denticulatum, Eucheuma cottonii, and Halymenia sp).Chlorophyceae (Caulerpa sp) and Phaeophyceae (brown algae) classes, namely Sargassum sp, Padina sp.Based on the nutritional content of macroalgae differs depending on the type, namely protein content (0.76 -45.63%), lipid (0.10 -6.20%), and ash (2.00 -17.12%) as relevant research, macroalgae can potentially be used as a source of additional feed and substitute for meal in rations by considering other compounds that can be toxic to livestock.

Figure 1 .
Figure 1.Macroalgae species cultivated in the coastal area of west Sulawesi.

Figure 2 .
Figure 2. Non-aquaculture macroalgae from the waters of the west coast of Sulawesi.

Table 1 .
Description of the morphology of the species and the content of nutrients possessed.